RISC-V: Enable Microchip PolarFire ICICLE SoC

Enable Microchip PolarFire ICICLE soc config in defconfig.
It allows the default upstream kernel to boot on PolarFire ICICLE board.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Bin Meng <bin.meng@windriver.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

arch/riscv/configs/defconfig

@@ -16,6 +16,7 @@ CONFIG_EXPERT=y
 CONFIG_BPF_SYSCALL=y
 CONFIG_SOC_SIFIVE=y
 CONFIG_SOC_VIRT=y
+CONFIG_SOC_MICROCHIP_POLARFIRE=y
 CONFIG_SMP=y
 CONFIG_HOTPLUG_CPU=y
 CONFIG_JUMP_LABEL=y
@@ -82,6 +83,9 @@ CONFIG_USB_OHCI_HCD=y
 CONFIG_USB_OHCI_HCD_PLATFORM=y
 CONFIG_USB_STORAGE=y
 CONFIG_USB_UAS=y
+CONFIG_MMC_SDHCI=y
+CONFIG_MMC_SDHCI_PLTFM=y
+CONFIG_MMC_SDHCI_CADENCE=y
 CONFIG_MMC=y
 CONFIG_MMC_SPI=y
 CONFIG_RTC_CLASS=y