drm/amdgpu: fix spelling mistake "Falied" -> "Failed"

There is a spelling mistake in a DRM_ERROR error message. Fix it.

This got lost in a merge, restore the fix.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 4afaa61d)