mx6: Avoid writing to read-only bits in imximage.cfg

If in case this is valid according to the latest datasheet, ignore this patch.
Acked-by: Marek Vasut <marex@denx.de>
diff --git a/board/freescale/mx6qarm2/imximage.cfg b/board/freescale/mx6qarm2/imximage.cfg
index ceecbf9..bf941a3 100644
--- a/board/freescale/mx6qarm2/imximage.cfg
+++ b/board/freescale/mx6qarm2/imximage.cfg
@@ -167,7 +167,7 @@
 DATA 4 0x020c4080 0x000003FF
 
 # enable AXI cache for VDOA/VPU/IPU
-DATA 4 0x020e0010 0xF00000FF
+DATA 4 0x020e0010 0xF00000CF
 # set IPU AXI-id0 Qos=0xf(bypass) AXI-id1 Qos=0x7
 DATA 4 0x020e0018 0x007F007F
 DATA 4 0x020e001c 0x007F007F