drm/ttm: optimize pool allocations a bit v2

[ Upstream commit 735c4664 ]

If we got a page pool use it as much as possible.

If we can't get more pages from the pool allocate as much as possible.

Only if that still doesn't work reduce the order and try again.

v2: minor cleanups

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221107195808.1873-1-christian.koenig@amd.com


Stable-dep-of: 379989e7 ("drm/ttm/pool: Fix ttm_pool_alloc error path")
Signed-off-by: Sasha Levin <sashal@kernel.org>