gpio: mpc8xxx: Rename Kconfig option, structures, and functions

Rename the Kconfig option, structures (and their members), as well as
functions of the mpc85xx driver to include mpc8xxx to reflect the more
generic usage.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
diff --git a/arch/powerpc/include/asm/arch-mpc85xx/gpio.h b/arch/powerpc/include/asm/arch-mpc85xx/gpio.h
index 76faa22..b2ba31e 100644
--- a/arch/powerpc/include/asm/arch-mpc85xx/gpio.h
+++ b/arch/powerpc/include/asm/arch-mpc85xx/gpio.h
@@ -18,7 +18,7 @@
 #include <asm/mpc85xx_gpio.h>
 #endif
 
-struct mpc85xx_gpio_plat {
+struct mpc8xxx_gpio_plat {
 	ulong addr;
 	unsigned long size;
 	uint ngpios;