V4L/DVB (11349): mx3-camera: adapt the clock definition and the driver to the new clock naming

With the i.MX31 transition to clkdev clock names have changed, but mistakenly
the "mx3-camera.0" has been registered with a non-NULL connection ID, which is
not necessary, since this is the only clock, used by the capture interface
driver. Fix the clock definition and the driver to use NULL as a connection ID.

Signed-off-by: Guennadi Liakhovetski <lg@denx.de>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>