USB: gadget: pxa25x: basic transceiver support

This adds very basic otg_transceiver support, with vbus_session
and vbus_draw callbacks.

Now VBUS sensing can be handled by an external driver which registers
the otg_transceiver interface. It also allows gadget drivers to configure
the current drawn from VBUS. The UDC driver just passes their requests
along to the transceiver driver.

Signed-off-by: Philipp Zabel <philipp.zabel@gmail.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/gadget/pxa25x_udc.h b/drivers/usb/gadget/pxa25x_udc.h
index 1d51aa2..f572c56 100644
--- a/drivers/usb/gadget/pxa25x_udc.h
+++ b/drivers/usb/gadget/pxa25x_udc.h
@@ -128,6 +128,7 @@
 	struct device				*dev;
 	struct clk				*clk;
 	struct pxa2xx_udc_mach_info		*mach;
+	struct otg_transceiver			*transceiver;
 	u64					dma_mask;
 	struct pxa25x_ep			ep [PXA_UDC_NUM_ENDPOINTS];