drm/amd/pp: Refine smu7/8 request_smu_load_fw callback function

The request_smu_load_fw of VI is used to load gfx/sdma
ip's firmware.

Check whether the gfx/sdma firmware have been loaded successfully
in this callback function.
if failed, driver can exit to avoid gpu hard hung.
if successful, clean the flag reload_fw to avoid duplicated fw load.
when suspend/resume, driver need to reload fw.
so in suspend, reset the reload_fw flag to true to enable load fw when
resume.

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>