usb: kconfig: replace PPC_OF with PPC

The PPC_OF is a ppc specific option which is used to mean that the
firmware device tree access functions are available. Since all the
ppc platforms have a device tree, it is aways set to 'y' for ppc.
So it makes no sense to keep a such option in the current kernel.
Replace it with PPC

Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/Kconfig

@@ -219,7 +219,7 @@ config USB_EHCI_TEGRA
 
 config USB_EHCI_HCD_PPC_OF
 	bool "EHCI support for PPC USB controller on OF platform bus"
-	depends on PPC_OF
+	depends on PPC
 	default y
 	---help---
 	  Enables support for the USB controller present on the PowerPC
@@ -494,7 +494,7 @@ config USB_OHCI_ATH79
 
 config USB_OHCI_HCD_PPC_OF_BE
 	bool "OHCI support for OF platform bus (big endian)"
-	depends on PPC_OF
+	depends on PPC
 	select USB_OHCI_BIG_ENDIAN_DESC
 	select USB_OHCI_BIG_ENDIAN_MMIO
 	---help---
@@ -503,7 +503,7 @@ config USB_OHCI_HCD_PPC_OF_BE
 
 config USB_OHCI_HCD_PPC_OF_LE
 	bool "OHCI support for OF platform bus (little endian)"
-	depends on PPC_OF
+	depends on PPC
 	select USB_OHCI_LITTLE_ENDIAN
 	---help---
 	  Enables support for little-endian USB controllers present on the
@@ -511,7 +511,7 @@ config USB_OHCI_HCD_PPC_OF_LE
 
 config USB_OHCI_HCD_PPC_OF
 	bool
-	depends on PPC_OF
+	depends on PPC
 	default USB_OHCI_HCD_PPC_OF_BE || USB_OHCI_HCD_PPC_OF_LE
 
 config USB_OHCI_HCD_PCI