drm/amd: Restore flashing support for PSP 13.0.10

This was accidentally lost by commit e6e3bee0 ("drm/amd: Use
attribute groups for PSP flashing attributes")

Fixes: e6e3bee0 ("drm/amd: Use attribute groups for PSP flashing attributes")
Reported-by:  <Likun.Gao@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>