media: v4l2-fwnode: Fix setting V4L2_MBUS_DATA_ACTIVE_HIGH/LOW flag

When parallel bus is used and data-active is being parsed, incorrect
flags are cleared.

Clear the correct flag bits.

Fixes: e9be1b86 (media: v4l: fwnode:
Use default parallel flags).

Cc: stable@vger.kernel.org # for Kernel 4.20
Signed-off-by: Ondrej Jirman <megous@megous.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>