usb: gadget: Fix data aborts during USB ethernet boot

As seen on GCC 4.6 Linaro compiler, control_req buffer is not aligned
on 4 byte boundaray causing data aborts in eth_setup -> conf_buf
during dhcp boot over usb_ether. Fix the issue my aligning control_req
buffer using DEFINE_CACHE_ALIGN_BUFFER.

Tested on am335x_evm platform (beaglebone).
Applies on 2013.10-rc1 branch.

Cc: Tom Rini <trini@ti.com>
Cc: Marek Vasut <marex@denx.de>
Signed-off-by: Joel Fernandes <joelf@ti.com>

drivers/usb/gadget/ether.c

@@ -849,9 +849,10 @@ static struct usb_gadget_strings	stringtab = {
 };
 
 /*============================================================================*/
-static u8 control_req[USB_BUFSIZ];
+DEFINE_CACHE_ALIGN_BUFFER(u8, control_req, USB_BUFSIZ);
+
 #if defined(CONFIG_USB_ETH_CDC) || defined(CONFIG_USB_ETH_RNDIS)
-static u8 status_req[STATUS_BYTECOUNT] __attribute__ ((aligned(4)));
+DEFINE_CACHE_ALIGN_BUFFER(u8, status_req, STATUS_BYTECOUNT);
 #endif