drm/amdgpu: Fix for BO move issue

A user reported a bug on CAPE VERDE system where uvd_v3_1
IP component failed to initialize as there is an issue with
BO move code from one memory to other.

In function amdgpu_mem_visible() called by amdgpu_bo_move(),
when there are no blocks to compare or if we have a single
block then break the loop.

Fixes: 312b4dc1 ("drm/amdgpu: Fix VRAM BO swap issue")
Signed-off-by: NArunpravin Paneer Selvam <Arunpravin.PaneerSelvam@amd.com>
Reviewed-by: NChristian König <christian.koenig@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

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

@@ -439,6 +439,9 @@ static bool amdgpu_mem_visible(struct amdgpu_device *adev,
 	while (cursor.remaining) {
 		amdgpu_res_next(&cursor, cursor.size);
 
+		if (!cursor.remaining)
+			break;
+
 		/* ttm_resource_ioremap only supports contiguous memory */
 		if (end != cursor.start)
 			return false;