staging: emxx_udc: Do not use comparisons on bool tests

This fixes the following coccinelle warning:
WARNING: Comparison of bool to 0/1

Signed-off-by: Roberta Dobrescu <roberta.dobrescu@gmail.com>
Acked-by: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>