Fix SAADC resolution set in sdk_config. analogin_read_u16 assumes 12-bit range but config was set to 10 bit range causing incorrect readings to be returned.

Author: AGlass0fMilk

targets/TARGET_NORDIC/TARGET_NRF5x/TARGET_NRF52/TARGET_MCU_NRF52840/config/sdk_config.h

@@ -3124,7 +3124,7 @@
 // <3=> 14 bit 
 
 #ifndef NRFX_SAADC_CONFIG_RESOLUTION
-#define NRFX_SAADC_CONFIG_RESOLUTION 1
+#define NRFX_SAADC_CONFIG_RESOLUTION 2
 #endif
 
 // <o> NRFX_SAADC_CONFIG_OVERSAMPLE  - Sample period