MAINTAINERS: Remove deleted platform efm32

There are no files left to be maintained, to remove the maintainer
entry, too.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20210115155130.185010-8-u.kleine-koenig@pengutronix.de'
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

MAINTAINERS

@@ -1807,13 +1807,6 @@ F:	drivers/firmware/turris-mox-rwtm.c
 F:	drivers/gpio/gpio-moxtet.c
 F:	include/linux/moxtet.h
 
-ARM/ENERGY MICRO (SILICON LABS) EFM32 SUPPORT
-M:	Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
-R:	Pengutronix Kernel Team <kernel@pengutronix.de>
-L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
-S:	Maintained
-N:	efm32
-
 ARM/EZX SMARTPHONES (A780, A910, A1200, E680, ROKR E2 and ROKR E6)
 M:	Robert Jarzmik <robert.jarzmik@free.fr>
 L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)