drm/nova: Align GEM memory allocation to system page size

drm/nova: Align GEM memory allocation to system page size

Use page::page_align for GEM object memory allocation to ensure the
allocation is page aligned. This is important on systems where the
default page size is not 4k. Such as 16k or 64k aarch64 systems.

This change uses the updated page_align() function which returns
Option<usize> for overflow safety. (See "rust: Return Option from
page_align and ensure no usize overflow").

Signed-off-by: Brendan Shephard <bshephar@bne-home.net>
Link: https://patch.msgid.link/20251215083416.266469-1-bshephar@bne-home.net
[ Import page module only. - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>