drm/radeon/kms: set a default max_pixel_clock

On some Power rv100 cards, we have no ATY OF table, but we have
no combios table either, and hence we refuse all modes on VGA-0
since we end up with a 0 max pixel clock.
Signed-off-by: NDave Airlie <airlied@redhat.com>
Cc: stable@kernel.org
Reviewed-by: NAlex Deucher <alexdeucher@gmail.com>
Reviewed-by: NJerome Glisse <jglisse@redhat.com>

drivers/gpu/drm/radeon/radeon_clocks.c

@@ -219,6 +219,9 @@ void radeon_get_clock_info(struct drm_device *dev)
 		} else {
 			DRM_INFO("Using generic clock info\n");
 
+			/* may need to be per card */
+			rdev->clock.max_pixel_clock = 35000;
+
 			if (rdev->flags & RADEON_IS_IGP) {
 				p1pll->reference_freq = 1432;
 				p2pll->reference_freq = 1432;