drm/amdgpu: fix an error code in init_pmu_entry_by_type_and_add()

drm/amdgpu: fix an error code in init_pmu_entry_by_type_and_add()

BugLink: https://bugs.launchpad.net/bugs/1929455
[ Upstream commit 90cb3d8aca1baea9471d28f28d5de1528dd5e424 ]

If the kmemdup() fails then this should return a negative error code
but it currently returns success

Fixes: b4a7db71ea06 ("drm/amdgpu: add per device user friendly xgmi events for vega20")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Kelsey Skunberg <kelsey.skunberg@canonical.com>