drm/radeon: fix bank tiling parameters on cayman

Handle the 16 bank case.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
diff --git a/drivers/gpu/drm/radeon/ni.c b/drivers/gpu/drm/radeon/ni.c
index 9945d86..853800e 100644
--- a/drivers/gpu/drm/radeon/ni.c
+++ b/drivers/gpu/drm/radeon/ni.c
@@ -574,10 +574,18 @@
 	if (rdev->flags & RADEON_IS_IGP)
 		rdev->config.cayman.tile_config |= 1 << 4;
 	else {
-		if ((mc_arb_ramcfg & NOOFBANK_MASK) >> NOOFBANK_SHIFT)
-			rdev->config.cayman.tile_config |= 1 << 4;
-		else
+		switch ((mc_arb_ramcfg & NOOFBANK_MASK) >> NOOFBANK_SHIFT) {
+		case 0: /* four banks */
 			rdev->config.cayman.tile_config |= 0 << 4;
+			break;
+		case 1: /* eight banks */
+			rdev->config.cayman.tile_config |= 1 << 4;
+			break;
+		case 2: /* sixteen banks */
+		default:
+			rdev->config.cayman.tile_config |= 2 << 4;
+			break;
+		}
 	}
 	rdev->config.cayman.tile_config |=
 		((gb_addr_config & PIPE_INTERLEAVE_SIZE_MASK) >> PIPE_INTERLEAVE_SIZE_SHIFT) << 8;