drm/amd/pp: Fix memory leak on CI/AI

On CI/AI, fw was not loaded by smu, but
smu's fw still need to be released
when driver fini.

Reviewed-by: Evan Quan <evan.quan@amd.com>
Signed-off-by: Rex Zhu <Rex.Zhu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>