ARM: efm32: select AUTO_ZRELADDR

The efm32 platform does not provide a zreladdr-y line its Makefile.boot,
so we always have to use CONFIG_AUTO_ZRELADDR in order to successfully
build and link a zImage.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Uwe Kleine-König <kernel@pengutronix.de>

arch/arm/Kconfig

@@ -420,6 +420,7 @@ config ARCH_EFM32
 	bool "Energy Micro efm32"
 	depends on !MMU
 	select ARCH_REQUIRE_GPIOLIB
+	select AUTO_ZRELADDR
 	select ARM_NVIC
 	# CLKSRC_MMIO is wrong here, but needed until a proper fix is merged,
 	# i.e. CLKSRC_EFM32 selecting CLKSRC_MMIO