ARM: drop efm32 platform

I didn't touch this code since it served as a platform to introduce
ARMv7-M support to Linux. The only known machine that runs Linux has only
4 MiB of RAM (that originally only exists to hold the display's framebuffer).

There are no known users and no further use foreseeable, so drop the
code.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20210115155130.185010-2-u.kleine-koenig@pengutronix.de'
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/arm/Kconfig

@@ -725,14 +725,6 @@ source "arch/arm/mach-zx/Kconfig"
 source "arch/arm/mach-zynq/Kconfig"
 
 # ARMv7-M architecture
-config ARCH_EFM32
-	bool "Energy Micro efm32"
-	depends on ARM_SINGLE_ARMV7M
-	select GPIOLIB
-	help
-	  Support for Energy Micro's (now Silicon Labs) efm32 Giant Gecko
-	  processors.
-
 config ARCH_LPC18XX
 	bool "NXP LPC18xx/LPC43xx"
 	depends on ARM_SINGLE_ARMV7M
@@ -1550,7 +1542,7 @@ config ARM_MODULE_PLTS
 config FORCE_MAX_ZONEORDER
 	int "Maximum zone order"
 	default "12" if SOC_AM33XX
-	default "9" if SA1111 || ARCH_EFM32
+	default "9" if SA1111
 	default "11"
 	help
 	  The kernel memory allocator divides physically contiguous memory

arch/arm/Kconfig.debug

@@ -1448,20 +1448,6 @@ choice
 		  options; the platform specific options are deprecated
 		  and will be soon removed.
 
-	config DEBUG_LL_UART_EFM32
-		bool "Kernel low-level debugging via efm32 UART"
-		depends on ARCH_EFM32
-		help
-		  Say Y here if you want the debug print routines to direct
-		  their output to an UART or USART port on efm32 based
-		  machines. Use the following addresses for DEBUG_UART_PHYS:
-
-		    0x4000c000 | USART0
-		    0x4000c400 | USART1
-		    0x4000c800 | USART2
-		    0x4000e000 | UART0
-		    0x4000e400 | UART1
-
 	config DEBUG_LL_UART_PL01X
 		bool "Kernel low-level debugging via ARM Ltd PL01x Primecell UART"
 		help
@@ -1579,7 +1565,6 @@ config DEBUG_LL_INCLUDE
 	default "debug/meson.S" if DEBUG_MESON_UARTAO
 	default "debug/pl01x.S" if DEBUG_LL_UART_PL01X || DEBUG_UART_PL01X
 	default "debug/exynos.S" if DEBUG_EXYNOS_UART
-	default "debug/efm32.S" if DEBUG_LL_UART_EFM32
 	default "debug/icedcc.S" if DEBUG_ICEDCC
 	default "debug/imx.S" if DEBUG_IMX1_UART || \
 				 DEBUG_IMX25_UART || \
@@ -1674,7 +1659,6 @@ config DEBUG_UART_PHYS
 	default 0x20201000 if DEBUG_BCM2835
 	default 0x3e000000 if DEBUG_BCM_KONA_UART
 	default 0x3f201000 if DEBUG_BCM2836
-	default 0x4000e400 if DEBUG_LL_UART_EFM32
 	default 0x40010000 if STM32MP1_DEBUG_UART
 	default 0x40011000 if STM32F4_DEBUG_UART || STM32F7_DEBUG_UART || \
 				STM32H7_DEBUG_UART
@@ -1759,7 +1743,6 @@ config DEBUG_UART_PHYS
 	default 0xfffff200 if DEBUG_AT91_RM9200_DBGU
 	depends on ARCH_EP93XX || \
 	        DEBUG_LL_UART_8250 || DEBUG_LL_UART_PL01X || \
-		DEBUG_LL_UART_EFM32 || \
 		DEBUG_UART_8250 || DEBUG_UART_PL01X || DEBUG_MESON_UARTAO || \
 		DEBUG_QCOM_UARTDM || DEBUG_R7S72100_SCIF2 || \
 		DEBUG_R7S9210_SCIF2 || DEBUG_R7S9210_SCIF4 || \

arch/arm/Makefile

@@ -168,7 +168,6 @@ machine-$(CONFIG_ARCH_CNS3XXX)		+= cns3xxx
 machine-$(CONFIG_ARCH_DAVINCI)		+= davinci
 machine-$(CONFIG_ARCH_DIGICOLOR)	+= digicolor
 machine-$(CONFIG_ARCH_DOVE)		+= dove
-machine-$(CONFIG_ARCH_EFM32)		+= efm32
 machine-$(CONFIG_ARCH_EP93XX)		+= ep93xx
 machine-$(CONFIG_ARCH_EXYNOS)		+= exynos
 machine-$(CONFIG_ARCH_FOOTBRIDGE)	+= footbridge

arch/arm/boot/dts/Makefile

@@ -177,8 +177,6 @@ dtb-$(CONFIG_ARCH_DAVINCI) += \
 	da850-lego-ev3.dtb
 dtb-$(CONFIG_ARCH_DIGICOLOR) += \
 	cx92755_equinox.dtb
-dtb-$(CONFIG_ARCH_EFM32) += \
-	efm32gg-dk3750.dtb
 dtb-$(CONFIG_ARCH_EXYNOS3) += \
 	exynos3250-artik5-eval.dtb \
 	exynos3250-monk.dtb \