drm/msm: Fix MSM_INFO_GET_IOVA with carveout

stable inclusion
from stable-5.10.20
commit b016a9f0c546a75319da0f8eb43b4b7a720d45f6
bugzilla: 50608

--------------------------------

[ Upstream commit 6cefa31e ]

The msm_gem_get_iova should be guarded with gpu != NULL and not aspace
!= NULL, because aspace is NULL when using vram carveout.

Fixes: 933415e2 ("drm/msm: Add support for private address space instances")

Signed-off-by: Iskren Chernev <iskren.chernev@gmail.com>
Tested-by: Alexey Minnekhanov <alexeymin@postmarketos.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Acked-by: Xie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>