amdgpu: Free/uninit vamgr_32 in theoretically correct order

vamgr_32 is a region inside general VAM range. It is better to free and
deinitialize it before general VAM range.

Reviewed-by: Edward O'Callaghan <funfunctor@folklore1984.net>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: Alex Xie <AlexBin.Xie@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>