media: cec.h: CEC_OP_REC_FLAG_ values were swapped

CEC_OP_REC_FLAG_NOT_USED is 0 and CEC_OP_REC_FLAG_USED is 1, not the
other way around.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Reported-by: Jiunn Chang <c0d1n61at3@gmail.com>
Cc: <stable@vger.kernel.org>      # for v4.10 and up
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>