[media] x86/mm/pat, drivers/media/ivtv: move pat warn and replace WARN() with pr_warn()

On built-in kernels this warning will always splat as this is part
of the module init. Fix that by shifting the PAT requirement check
out under the code that does the "quasi-probe" for the device. This
device driver relies on an existing driver to find its own devices,
it looks for that device driver and its own found devices, then
uses driver_for_each_device() to try to see if it can probe each of
those devices as a frambuffer device with ivtvfb_init_card(). We
tuck the PAT requiremenet check then on the ivtvfb_init_card()
call making the check at least require an ivtv device present
before complaining.

Reported-by: Fengguang Wu <fengguang.wu@intel.com> [0-day test robot]
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>