radeon: fix fog coordinate emit

Noticed by dungeon on phoronix:
http://phoronix.com/forums/showthread.php?65408-Radeon-R100-R200-Mesa-Driver-Sees-Attention&p=247018#post247018

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Note: this is a candidate for the stable branches.

src/mesa/drivers/dri/radeon/radeon_maos_arrays.c

@@ -66,7 +66,7 @@ static void emit_vecfog(struct gl_context *ctx, struct radeon_aos *aos,
       aos->stride = 0;
    }
    else {
-      radeonAllocDmaRegion(rmesa, &aos->bo, &aos->offset, size * 4, 32);
+      radeonAllocDmaRegion(rmesa, &aos->bo, &aos->offset, size * count * 4, 32);
       aos->stride = size;
    }