drm/radeon: fix bank information in tiling config

While there are cards with more than 8 mem banks, the max
number of banks from a tiling perspective is 8, so cap
the tiling config at 8 banks.

Fixes:
https://bugs.freedesktop.org/show_bug.cgi?id=43448

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/ni.c b/drivers/gpu/drm/radeon/ni.c
index ce4e7cc..15f950c 100644
--- a/drivers/gpu/drm/radeon/ni.c
+++ b/drivers/gpu/drm/radeon/ni.c
@@ -866,9 +866,12 @@
 	/* num banks is 8 on all fusion asics. 0 = 4, 1 = 8, 2 = 16 */
 	if (rdev->flags & RADEON_IS_IGP)
 		rdev->config.cayman.tile_config |= 1 << 4;
-	else
-		rdev->config.cayman.tile_config |=
-			((mc_arb_ramcfg & NOOFBANK_MASK) >> NOOFBANK_SHIFT) << 4;
+	else {
+		if ((mc_arb_ramcfg & NOOFBANK_MASK) >> NOOFBANK_SHIFT)
+			rdev->config.cayman.tile_config |= 1 << 4;
+		else
+			rdev->config.cayman.tile_config |= 0 << 4;
+	}
 	rdev->config.cayman.tile_config |=
 		((gb_addr_config & PIPE_INTERLEAVE_SIZE_MASK) >> PIPE_INTERLEAVE_SIZE_SHIFT) << 8;
 	rdev->config.cayman.tile_config |=