drm/amd: Add Suspend/Hibernate notification callback support

As part of the suspend sequence VRAM needs to be evicted on dGPUs.
In order to make suspend/resume more reliable we moved this into
the pmops prepare() callback so that the suspend sequence would fail
but the system could remain operational under high memory usage suspend.

Another class of issues exist though where due to memory fragementation
there isn't a large enough contiguous space and swap isn't accessible.

Add support for a suspend/hibernate notification callback that could
evict VRAM before tasks are frozen. This should allow paging out to swap
if necessary.

Link: https://github.com/ROCm/ROCK-Kernel-Driver/issues/174
Link: drm/amd#3476
Closes: drm/amd#2362
Closes: drm/amd#3781


Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Link: https://lore.kernel.org/r/20241128032656.2090059-2-superm1@kernel.org


Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>