staging: emxx_udc: Replace GFP_KERNEL with GFP_ATOMIC

To avoid deadlock, do not call blocking functions with spinlocks held.

Replace GFP_KERNEL with GFP_ATOMIC, as the latter will fail if the pile
doesn't have enough free pages but will not sleep and hence deadlock can
be avoided.

Found by Coccinelle.

Signed-off-by: Tapasweni Pathak <tapaswenipathak@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>