LU-17504 libcfs: safer LIBCFS_ALLOC

LU-17504 libcfs: safer LIBCFS_ALLOC

Make the LIBCFS_ALLOC() family of macros safer by adding
parenthesis around arguments such as (size) to avoid uninteded
expansion.

CoverityID: 415056 ("Integer handling issues")

Fixes: 718e3f3e68 ("LU-17504 build: fix gcc-13 [-Werror=stringop-overread] error")
Signed-off-by: Shaun Tancheff <shaun.tancheff@hpe.com>
Change-Id: I9701f87025bc5ce038a6bf34413b64a3f019d998
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/55015
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Oleg Drokin <green@whamcloud.com>