USB: move common alchemy USB routines to arch/mips/alchemy/common.c

A previous patch converted the Alchemy platform to use the OHCI and EHCI
platform drivers. As a result, all the common logic to handle USB present in
drivers/usb/host/alchemy-common.c has no reason to remain here, so we move it
to arch/mips/alchemy/common/usb.c which is a more appropriate place. This
change was suggested by Manuel Lauss.

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>

arch/mips/alchemy/common/Makefile

@@ -6,7 +6,7 @@
 #
 
 obj-y += prom.o time.o clocks.o platform.o power.o setup.o \
-	sleeper.o dma.o dbdma.o vss.o irq.o
+	sleeper.o dma.o dbdma.o vss.o irq.o usb.o
 
 # optional gpiolib support
 ifeq ($(CONFIG_ALCHEMY_GPIO_INDIRECT),)