MIPS: Alchemy: use the OHCI platform driver

Convert the Alchemy platform to register the ohci-platform driver, now that
the ohci-platform driver properly handles the specific ohci-au1xxx resume
from suspend case.

This also greatly simplifies the power_{on,off} callbacks and make them
work on platform device id instead of checking the OHCI controller base
address like what was done in ohci-au1xxx.c.

Impacted defconfigs are also updated accordingly to select the OHCI platform
driver.

Signed-off-by: Florian Fainelli <florian@openwrt.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/arch/mips/configs/gpr_defconfig b/arch/mips/configs/gpr_defconfig
index 48a40ae..fb64589 100644
--- a/arch/mips/configs/gpr_defconfig
+++ b/arch/mips/configs/gpr_defconfig
@@ -291,6 +291,7 @@
 CONFIG_USB_EHCI_HCD=y
 CONFIG_USB_EHCI_ROOT_HUB_TT=y
 CONFIG_USB_OHCI_HCD=y
+CONFIG_USB_OHCI_HCD_PLATFORM=y
 CONFIG_USB_STORAGE=m
 CONFIG_USB_LIBUSUAL=y
 CONFIG_USB_SERIAL=y