gpio: mpc85xx: Rename driver file to mpc8xxx

In preparation to making the MPC85xx GPIO driver useable for a broader
range of SoCs, rename the driver file.
Signed-off-by: NMario Six <mario.six@gdsys.cc>

drivers/gpio/Makefile

@@ -38,7 +38,7 @@ obj-$(CONFIG_DA8XX_GPIO)	+= da8xx_gpio.o
 obj-$(CONFIG_DM644X_GPIO)	+= da8xx_gpio.o
 obj-$(CONFIG_ALTERA_PIO)	+= altera_pio.o
 obj-$(CONFIG_MPC83XX_GPIO)	+= mpc83xx_gpio.o
-obj-$(CONFIG_MPC85XX_GPIO)	+= mpc85xx_gpio.o
+obj-$(CONFIG_MPC85XX_GPIO)	+= mpc8xxx_gpio.o
 obj-$(CONFIG_SH_GPIO_PFC)	+= sh_pfc.o
 obj-$(CONFIG_OMAP_GPIO)	+= omap_gpio.o
 obj-$(CONFIG_DB8500_GPIO)	+= db8500_gpio.o