drm/amdkfd: Add sync after creating vram bo

drm/amdkfd: Add sync after creating vram bo

[ Upstream commit ba029e9991d9be90a28b6a0ceb25e9a6fb348829 ]

There will be data corruption on vram allocated by svm
if the initialization is not complete and application is
writting on the memory. Adding sync to wait for the
initialization completion is to resolve this issue.

Signed-off-by: Eric Huang <jinhuieric.huang@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>