drm/amdgpu: Skip the program of MMMC_VM_AGP_* in SRIOV

KMD should not program these registers, the value were
defined in the host, so skip them in the SRIOV environment.
Signed-off-by: NPeng Ju Zhou <PengJu.Zhou@amd.com>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/mmhub_v2_0.c

@@ -224,12 +224,12 @@ static void mmhub_v2_0_init_system_aperture_regs(struct amdgpu_device *adev)
 	uint64_t value;
 	uint32_t tmp;
 
-	/* Program the AGP BAR */
-	WREG32_SOC15_RLC(MMHUB, 0, mmMMMC_VM_AGP_BASE, 0);
-	WREG32_SOC15_RLC(MMHUB, 0, mmMMMC_VM_AGP_BOT, adev->gmc.agp_start >> 24);
-	WREG32_SOC15_RLC(MMHUB, 0, mmMMMC_VM_AGP_TOP, adev->gmc.agp_end >> 24);
-
 	if (!amdgpu_sriov_vf(adev)) {
+		/* Program the AGP BAR */
+		WREG32_SOC15_RLC(MMHUB, 0, mmMMMC_VM_AGP_BASE, 0);
+		WREG32_SOC15_RLC(MMHUB, 0, mmMMMC_VM_AGP_BOT, adev->gmc.agp_start >> 24);
+		WREG32_SOC15_RLC(MMHUB, 0, mmMMMC_VM_AGP_TOP, adev->gmc.agp_end >> 24);
+
 		/* Program the system aperture low logical page number. */
 		WREG32_SOC15(MMHUB, 0, mmMMMC_VM_SYSTEM_APERTURE_LOW_ADDR,
 			     min(adev->gmc.fb_start, adev->gmc.agp_start) >> 18);