drm/amdgpu: correct reference clock value on vega10

Old value from bringup was wrong.

Cc: stable@vger.kernel.org
Signed-off-by: Ken Wang <Ken.Wang@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/soc15.c

@@ -279,10 +279,7 @@ static void soc15_init_golden_registers(struct amdgpu_device *adev)
 }
 static u32 soc15_get_xclk(struct amdgpu_device *adev)
 {
-	if (adev->asic_type == CHIP_VEGA10)
-		return adev->clock.spll.reference_freq/4;
-	else
-		return adev->clock.spll.reference_freq;
+	return adev->clock.spll.reference_freq;
 }