V4L/DVB (11901): v4l2: Create helper function for bounding and aligning images

Most hardware has limits on minimum and maximum image dimensions and also
requirements about alignment.  For example, image width must be even or a
multiple of four.  Some hardware has requirements that the total image size
(width * height) be a multiple of some power of two.

v4l_bound_align_image() will enforce min and max width and height, power of
two alignment on width and height, and power of two alignment on total
image size.

It uses an efficient algorithm that will try to find the "closest" image
size that meets the requirements.

Signed-off-by: Trent Piepho <xyzzy@speakeasy.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>