usb: dwc3: ep0: fix sparc64 build

drivers/usb/dwc3/ep0.c: In function `__dwc3_ep0_do_control_data':
drivers/usb/dwc3/ep0.c:905: error: `typeof' applied to a bit-field

Looks like a gcc-3.4.5/sparc64 bug.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Felipe Balbi <balbi@ti.com>