soc: nordic: nRF54L: Move a few options from boards to the SoC definition

A few option defaults that were so far defined in the board _defconfig
files are actually entirely SoC family (nRF54L) dependant, so it makes
much more sense to have them defined at the SoC family level in order
for all boards based on these SoCs to automatically inherit them.

Signed-off-by: Carles Cufi <carles.cufi@nordicsemi.no>

soc/nordic/nrf54l/Kconfig.defconfig

@@ -12,9 +12,26 @@ if ARM
 config CORTEX_M_SYSTICK
 	default !NRF_GRTC_TIMER
 
+# Start SYSCOUNTER on driver init
+config NRF_GRTC_START_SYSCOUNTER
+	default NRF_GRTC_TIMER
+
 config CACHE_NRF_CACHE
 	default y if EXTERNAL_CACHE
 
+config CACHE_MANAGEMENT
+	default y
+
+choice CACHE_TYPE
+	default EXTERNAL_CACHE
+endchoice
+
+# MPU-based null-pointer dereferencing detection cannot
+# be applied as the (0x0 - 0x400) is unmapped for this target.
+choice NULL_POINTER_EXCEPTION_DETECTION
+	default NULL_POINTER_EXCEPTION_DETECTION_NONE
+endchoice
+
 endif # ARM
 
 if RISCV