rt2x00: checkpatch.pl error fixes for rt2x00dev.c

rt2x00dev.c:689: ERROR: spaces required around that '=' (ctx:WxV)

Signed-off-by: Mark Einon <mark.einon@gmail.com>
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>