drm/amdgpu: Fix TLB invalidation request when using semaphore

drm/amdgpu: Fix TLB invalidation request when using semaphore

[ Upstream commit 37c58ddf57364d1a636850bb8ba6acbe1e16195e ]

Use a more meaningful variable name for the invalidation request
that is distinct from the tmp variable that gets overwritten when
acquiring the invalidation semaphore.

Fixes: 4ed8a03740d0 ("drm/amdgpu: invalidate mmhub semaphore workaround in gmc9/gmc10")
Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Yong Zhao <Yong.Zhao@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>