soc: arm: fix missing configs & defines

Some SoC have missing feature selections in their Kconfig.
Some others are missing includes of CMSIS-Core headers.

Signed-off-by: Wilfried Chauveau <wilfried.chauveau@arm.com>

soc/arm/silabs_exx32/efm32hg/Kconfig.series

@@ -9,6 +9,7 @@ config SOC_SERIES_EFM32HG
 	select CPU_CORTEX_M0PLUS
 	select SOC_FAMILY_EXX32
 	select CPU_CORTEX_M_HAS_SYSTICK
+	select CPU_CORTEX_M_HAS_VTOR
 	select HAS_SILABS_GECKO
 	select SOC_GECKO_CMU
 	select SOC_GECKO_GPIO

soc/arm/silabs_exx32/efr32mg21/Kconfig.series

@@ -11,6 +11,7 @@ config SOC_SERIES_EFR32MG21
 	select ARMV8_M_DSP
 	select CPU_HAS_FPU
 	select CPU_HAS_ARM_MPU
+	select CPU_HAS_ARM_SAU
 	select SOC_FAMILY_EXX32
 	select SOC_GECKO_HAS_RADIO
 	select SOC_GECKO_SERIES2