[nrf fromlist] soc: Tune capacitor for LFXO for nRF53 and update accuracy

Switch from using internal 6pf to internal 7pf load capacitor for LFXO.
Use a default clock accuracy of 50PPM as this matches lab results.

50PPM should be sufficient for common operating temperatures of
25degC +- 15.

Upstream PR: zephyrproject-rtos/zephyr#36124

Signed-off-by: Johan Stridkvist <[email protected]>
(cherry picked from commit b7693fb)

Author: jostn

drivers/clock_control/Kconfig.nrf

@@ -120,7 +120,7 @@ endif # CLOCK_CONTROL_NRF_K32SRC_RC_CALIBRATION
 choice CLOCK_CONTROL_NRF_ACCURACY_PPM
 	prompt "32KHz clock accuracy"
 	default CLOCK_CONTROL_NRF_K32SRC_500PPM if CLOCK_CONTROL_NRF_K32SRC_RC
-	default CLOCK_CONTROL_NRF_K32SRC_20PPM
+	default CLOCK_CONTROL_NRF_K32SRC_50PPM
 
 config CLOCK_CONTROL_NRF_K32SRC_500PPM
 	bool "251 ppm to 500 ppm"

soc/arm/nordic_nrf/nrf53/Kconfig.soc

@@ -147,7 +147,7 @@ config SOC_ENABLE_LFXO
 choice SOC_LFXO_LOAD_CAPACITANCE
 	prompt "LFXO load capacitance"
 	depends on SOC_ENABLE_LFXO
-	default SOC_LFXO_CAP_INT_6PF
+	default SOC_LFXO_CAP_INT_7PF
 
 config SOC_LFXO_CAP_EXTERNAL
 	bool "Use external load capacitors"