[media] v4l: vsp1: Clean up file handle in open() error path

v4l2_fh_init is already done. So call the v4l2_fh_exit in error
condition before returing from the function.

Signed-off-by: Shailendra Verma <shailendra.v@samsung.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>