staging: emxx_udc: Fix invalid reference error

staging: emxx_udc: Fix invalid reference error

This patch fixes an invalid reference error by moving the code that
is executed when a queue element is found, into the loop. Also, it
removes an unnecessary test that now checks if the element is not
present in the queue.
Issue found by Coccinelle.

Signed-off-by: Javier F. Arias <jarias.linux@gmail.com>
Link: https://lore.kernel.org/r/20191030030419.mmnrzm7hr4encfai@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>