powerpc: Move 8xxx GPIO Kconfig under the platform menu

The initial patch had the option at the top level which wasn't
quite right.  Moving under the platform options is a bit better.
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

arch/powerpc/platforms/Kconfig

@@ -293,4 +293,13 @@ config OF_RTC
 
 source "arch/powerpc/sysdev/bestcomm/Kconfig"
 
+config MPC8xxx_GPIO
+	bool "MPC8xxx GPIO support"
+	depends on PPC_MPC831x || PPC_MPC834x || PPC_MPC837x || PPC_85xx || PPC_86xx
+	select GENERIC_GPIO
+	select ARCH_REQUIRE_GPIOLIB
+	help
+	  Say Y here if you're going to use hardware that connects to the
+	  MPC831x/834x/837x/8572/8610 GPIOs.
+
 endmenu

arch/powerpc/sysdev/Kconfig

@@ -7,15 +7,6 @@ config PPC4xx_PCI_EXPRESS
 	depends on PCI && 4xx
 	default n
 
-config MPC8xxx_GPIO
-	bool "MPC8xxx GPIO support"
-	depends on PPC_MPC831x || PPC_MPC834x || PPC_MPC837x || PPC_85xx || PPC_86xx
-	select GENERIC_GPIO
-	select ARCH_REQUIRE_GPIOLIB
-	help
-	  Say Y here if you're going to use hardware that connects to the
-	  MPC831x/834x/837x/8572/8610 GPIOs.
-
 config PPC_MSI_BITMAP
 	bool
 	depends on PCI_MSI