drm/amdgpu: Optimize RAS TA initialization and TA unload funcs

[ Upstream commit bf7d7772 ]

1. Save TA unload psp response status
2. Add RAS TA loading status check for initializaiton
3. Drop RAS context teardown to allow RAS TA to be reloaded

Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Candice Li <candice.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Stable-dep-of: 467e00b3 ("drm/amd/amdgpu: Fix missing error return on kzalloc failure")
Signed-off-by: Sasha Levin <sashal@kernel.org>