powerpc/mpc5200: Make mpc5200 GPIO driver select the GENERIC_GPIO config

CONFIG_GENERIC_GPIO is needed for the gpio driver to work.
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>

arch/powerpc/platforms/52xx/Kconfig

@@ -46,6 +46,7 @@ config PPC_MPC5200_BUGFIX
 config PPC_MPC5200_GPIO
 	bool "MPC5200 GPIO support"
 	depends on PPC_MPC52xx
+	select GENERIC_GPIO
 	select HAVE_GPIO_LIB
 	help
 	  Enable gpiolib support for mpc5200 based boards