ARM: add ARM_SINGLE_ARMV7M in ARMv7-M defconfigs

Select ARM_SINGLE_ARMV7M in defconfigs of the converted ARMv7-M
platforms.

[arnd: moved the efm32_defconfig change to the patch that
originally introduces the symbol, to avoid intermittent regression]
Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/arm/configs/efm32_defconfig

@@ -85,7 +85,6 @@ CONFIG_GPIO_SYSFS=y
 # CONFIG_USB_SUPPORT is not set
 CONFIG_MMC=y
 CONFIG_MMC_SPI=y
-# CONFIG_IOMMU_SUPPORT is not set
 CONFIG_EXT2_FS=y
 # CONFIG_FILE_LOCKING is not set
 # CONFIG_DNOTIFY is not set

arch/arm/configs/lpc18xx_defconfig

@@ -22,6 +22,7 @@ CONFIG_EMBEDDED=y
 # CONFIG_IOSCHED_DEADLINE is not set
 # CONFIG_IOSCHED_CFQ is not set
 # CONFIG_MMU is not set
+CONFIG_ARM_SINGLE_ARMV7M=y
 CONFIG_ARCH_LPC18XX=y
 CONFIG_SET_MEM_PARAM=y
 CONFIG_DRAM_BASE=0x28000000

arch/arm/configs/stm32_defconfig

@@ -18,6 +18,7 @@ CONFIG_EMBEDDED=y
 # CONFIG_IOSCHED_DEADLINE is not set
 # CONFIG_IOSCHED_CFQ is not set
 # CONFIG_MMU is not set
+CONFIG_ARM_SINGLE_ARMV7M=y
 CONFIG_ARCH_STM32=y
 CONFIG_SET_MEM_PARAM=y
 CONFIG_DRAM_BASE=0x90000000