The mx6sl/mx6sx has 2 OTG and 1 host. So they have name
"USBO2H_USB_BASE_ADDR" in imx-regs.h. The driver hard codes
the USB base address name to "USBOH3", which causes the driver
failed to build for mx6sl/mx6sx.
This patch uniform the address name to "USB_BASE_ADDR" for all
mx6 series.
Signed-off-by: Ye.Li <B37916@freescale.com>