drm/amdgpu: Fix RLC safe mode test in gfx_v9_0_enter_rlc_safe_mode

We were testing the register offset, instead of the value stored in the
register, therefore always timing out the loop.

This reduces suspend time of the system in the bug report below by ~600
ms.

Cc: stable@vger.kernel.org
Bugzilla: https://bugs.freedesktop.org/107277Tested-by: NPaul Menzel <pmenzel@molgen.mpg.de>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Reviewed-by: NJunwei Zhang <Jerry.Zhang@amd.com>
Signed-off-by: NMichel Dänzer <michel.daenzer@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c

@@ -3490,7 +3490,7 @@ static void gfx_v9_0_enter_rlc_safe_mode(struct amdgpu_device *adev)
 
 		/* wait for RLC_SAFE_MODE */
 		for (i = 0; i < adev->usec_timeout; i++) {
-			if (!REG_GET_FIELD(SOC15_REG_OFFSET(GC, 0, mmRLC_SAFE_MODE), RLC_SAFE_MODE, CMD))
+			if (!REG_GET_FIELD(RREG32_SOC15(GC, 0, mmRLC_SAFE_MODE), RLC_SAFE_MODE, CMD))
 				break;
 			udelay(1);
 		}