gt: Add zalloc function
gt: Add zalloc function

Change-Id: Ifd4de1238edf4ab95a65a5006e6761e7618e8bee
Signed-off-by: Pawel Szewczyk <1691dcf8dab804b326e5e4b9ab228a1c3b23a2f2@samsung.com>

kopasiak/gt,kopasiak/gt