LU-5304: no need to zero out the allocated memory when GFP_ZERO is set

LU-5304: no need to zero out the allocated memory when GFP_ZERO is set

The kernel will zero out the memory allocated when GFP_ZERO is set,
so no need to zero it out again.

It is possible the original intent was to memset the allocated memory
if GFP_ZERO was not set. However the only two existing callers of this
function already set GFP_ZERO.

Signed-off-by: Frank Zago <fzago@cray.com>
Change-Id: Ia7f365f91aa2ce7a302e4f794706c978222317bb
Reviewed-on: http://review.whamcloud.com/11011
Reviewed-by: Patrick Farrell <paf@cray.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Jenkins
Reviewed-by: James Simmons <uja.ornl@gmail.com>
Reviewed-by: Liang Zhen <liang.zhen@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>