[PATCH] USB: fix bug in cypress_cy7c63.c driver

This was pointed out by Adrian Bunk <bunk@stusta.de>, as found by the Coverity Checker.

Cc: Adrian Bunk <bunk@stusta.de>
Cc: Oliver Bock <o.bock@fh-wolfenbuettel.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>