commit786fa584edupstream. When the "xclk" clock was added, it was made mandatory. This broke the driver on an OLPC plaform which doesn't know such clock. Make it optional. Tested on a OLPC XO-1 laptop. Fixes:0a024d634c("[media] ov7670: get xclk") Cc: stable@vger.kernel.org # 4.11+ Signed-off-by: Lubomir Rintel <lkundrak@v3.sk> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>