drm/amd: Don't init MEC2 firmware when it fails to load

The same calls are made directly above, but conditional on the firmware
loading and validating successfully.

Cc: stable@vger.kernel.org
Fixes: 9931b676 ("drm/amd: Load GFX10 microcode during early_init")
Signed-off-by: David McFarland <corngood@gmail.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>