libpayload: Fix data cache cleaning on ARM.

A similar fix was made to coreboot where OP_DCCSW was silently not doing
anything in dcache_op_set_way.

BUG=chrome-os-partner:19420
TEST=Built and booted on pit and snow.
BRANCH=None

Change-Id: Ia0798aef0cd02da7d1a14b7affa05038a002ab3b
Signed-off-by: Gabe Black <gabeblack@google.com>
Reviewed-on: https://gerrit.chromium.org/gerrit/66236
Reviewed-by: David Hendricks <dhendrix@chromium.org>
Commit-Queue: Gabe Black <gabeblack@chromium.org>
Tested-by: Gabe Black <gabeblack@chromium.org>

payloads/libpayload/arch/armv7/cache.c

@@ -143,6 +143,9 @@ static void dcache_op_set_way(enum dcache_op op)
 			case OP_DCISW:
 				dcisw(val);
 				break;
+			case OP_DCCSW:
+				dccsw(val);
+				break;
 			default:
 				break;
 			}