usb_device.h: Add missing header guards

BUG=b:143389556
BRANCH=none
TEST=builds

Change-Id: If7b480e213ba9c87e90ff6a69696c65280988cfb
Signed-off-by: Edward O'Callaghan <quasisec@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/flashrom/+/2032908
Tested-by: Edward O'Callaghan <quasisec@chromium.org>
Commit-Queue: Edward O'Callaghan <quasisec@chromium.org>
Reviewed-by: Sam McNally <sammc@chromium.org>
1 file changed