drm/amdgpu: Skip the program of MMMC_VM_AGP_* in SRIOV on MMHUB v3_0_0

[Why]
VF should not program these registers, the value were defined in the host.

[How]
Skip writing them in SRIOV environment and program them on host side.
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Yifan Zha <Yifan.Zha@amd.com>
Signed-off-by: Horace Chen <horace.chen@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/mmhub_v3_0.c

@@ -169,17 +169,17 @@ static void mmhub_v3_0_init_system_aperture_regs(struct amdgpu_device *adev)
 	uint64_t value;
 	uint32_t tmp;
 
-	/* Disable AGP. */
-	WREG32_SOC15(MMHUB, 0, regMMMC_VM_AGP_BASE, 0);
-	WREG32_SOC15(MMHUB, 0, regMMMC_VM_AGP_TOP, 0);
-	WREG32_SOC15(MMHUB, 0, regMMMC_VM_AGP_BOT, 0x00FFFFFF);
-
 	if (!amdgpu_sriov_vf(adev)) {
 		/*
 		 * the new L1 policy will block SRIOV guest from writing
 		 * these regs, and they will be programed at host.
 		 * so skip programing these regs.
 		 */
+		/* Disable AGP. */
+		WREG32_SOC15(MMHUB, 0, regMMMC_VM_AGP_BASE, 0);
+		WREG32_SOC15(MMHUB, 0, regMMMC_VM_AGP_TOP, 0);
+		WREG32_SOC15(MMHUB, 0, regMMMC_VM_AGP_BOT, 0x00FFFFFF);
+
 		/* Program the system aperture low logical page number. */
 		WREG32_SOC15(MMHUB, 0, regMMMC_VM_SYSTEM_APERTURE_LOW_ADDR,
 			     adev->gmc.vram_start >> 18);