drm/amdgpu: remove redundant AMDGPU_HAS_VRAM

drm/amdgpu: remove redundant AMDGPU_HAS_VRAM

AMDGPU_HAS_VRAM is redundant with is_app_apu, as both refer to
APUs with no carve-out. Since AMDGPU_HAS_VRAM only occurs once,
remove AMDGPU_HAS_VRAM definition. The tmr allocation can be covered
with AMDGPU_GEM_DOMAIN_GTT | AMDGPU_GEM_DOMAIN_VRAM in both vram and
non vram ASICs.

Signed-off-by: Yifan Zhang <yifan1.zhang@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>