drivers: serial: Microchip MEC5 add select PINCTRL to Kconfig

Zephyr has changed the rules for PINCTRL to use Kconfig select
feature at the driver level instead of setting the Kconfig
item directly in the board or application level. We updated
the MEC5 UART serial driver Kconfig to select PINCTRL.

Signed-off-by: Scott Worley <scott.worley@microchip.com>

drivers/serial/Kconfig.mec5

@@ -7,6 +7,7 @@ config UART_MCHP_MEC5
 	bool "Microchip MEC5 family ns16550 compatible UART driver"
 	default y
 	depends on DT_HAS_MICROCHIP_MEC5_UART_ENABLED
+	select PINCTRL
 	select SERIAL_HAS_DRIVER
 	select SERIAL_SUPPORT_INTERRUPT
 	help