media: atomisp: remove hmm_page_object

hmm_page_object only stores a struct page pointer, so we can just use
the hmm_bo.pages page pointer array everywhere.

Link: https://lore.kernel.org/linux-media/20220615205037.16549-33-hdegoede@redhat.com


Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>