soc: arm: nordic_nrf: Disable UART runtime configuration

Since it takes 400 bytes of code and it is rarely used disable
by default this feature.

Signed-off-by: Krzysztof Chruściński <krzysztof.chruscinski@nordicsemi.no>

doc/releases/migration-guide-3.6.rst

@@ -204,6 +204,10 @@ Device Drivers and Device Tree
                      <&rcc STM32_SRC_PLL1_Q FDCAN_SEL(1)>;
     };
 
+* Runtime configuration is now disabled by default for Nordic UART drivers. The motivation for the
+  change is that this feature is rarely used and disabling it significantly reduces the memory
+  footprint.
+
 Power Management
 ================
 

soc/arm/nordic_nrf/Kconfig.defconfig

@@ -40,4 +40,7 @@ config GPIO
 	default y
 	depends on SPI
 
+config UART_USE_RUNTIME_CONFIGURE
+	default n
+
 endif # SOC_FAMILY_NRF