usb/gadget/pch_udc: Fix compile error

Greg's e-mail address was old. So, I resend it.

Though I've tested this patch,
http://marc.info/?l=linux-usb&m=132825305710285&w=2,
I've received the following reports.
http://kisskb.ellerman.id.au/kisskb/buildresult/5771890/
http://kisskb.ellerman.id.au/kisskb/buildresult/5771905/

So, I added header file for these symbols.
Using this patch, this compile error must be disappeared.

Reported-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Tomoya MORINAGA <tomoya.rohm@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>