drm/radeon: fix bank information in tiling config

commit 29d654067a98c1cb8874c774e5fd799a038af8a6 upstream.

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>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/radeon/evergreen.c b/drivers/gpu/drm/radeon/evergreen.c
index cfa372c..03f4217 100644
--- a/drivers/gpu/drm/radeon/evergreen.c
+++ b/drivers/gpu/drm/radeon/evergreen.c
@@ -2136,9 +2136,12 @@
 	/* num banks is 8 on all fusion asics. 0 = 4, 1 = 8, 2 = 16 */
 	if (rdev->flags & RADEON_IS_IGP)
 		rdev->config.evergreen.tile_config |= 1 << 4;
-	else
-		rdev->config.evergreen.tile_config |=
-			((mc_arb_ramcfg & NOOFBANK_MASK) >> NOOFBANK_SHIFT) << 4;
+	else {
+		if ((mc_arb_ramcfg & NOOFBANK_MASK) >> NOOFBANK_SHIFT)
+			rdev->config.evergreen.tile_config |= 1 << 4;
+		else
+			rdev->config.evergreen.tile_config |= 0 << 4;
+	}
 	rdev->config.evergreen.tile_config |=
 		((mc_arb_ramcfg & BURSTLENGTH_MASK) >> BURSTLENGTH_SHIFT) << 8;
 	rdev->config.evergreen.tile_config |=