drm/amd/amdgpu: Only reserve vram for firmware with vega9 MS_HYPERV host.

driver loading failed on VEGA10 SRIOV VF with linux host due to a wide
range of stolen reserved vram.
Since VEGA10 SRIOV VF need to reserve vram for firmware with windows
Hyper_V host specifically, check hypervisor type to only reserve
memory for it, and the range of the reserved vram can be limited
to between 5M-7M area.

Fixes: faad5cca ("drm/amdgpu: Add stolen reserved memory for MI25 SRIOV.")
Signed-off-by: Yongqiang Sun <yongqiang.sun@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>