media: ti-vpe: cal: Iterate over correct number of CAMERARX instances

When performing operations on all CAMERARX instances, code usually
iterates over all cal->phy[] entries and skips the NULL pointers. The
number of available CAMERARX instances is however available through
cal->data->num_csi2_phy. Use it instead.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Benoit Parrot <bparrot@ti.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>