media: ti-vpe: cal: Rename MAX_(WIDTH|HEIGHT)_* macros with CAL_ prefix

The MAX_WIDTH_BYTES and MAX_HEIGHT_LINES macros have a generic name that
is prone to namespace clashes. Rename them with a CAL_ prefix. While at
it, expand their documentation and add CAL_MIN_(WIDTH|HEIGHT)_* macros
that will be used to implement CAMERARX subdev operations.

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>