build: fix meson warning

build: fix meson warning

This is to fix the unnecessary warning output, it is not consistent with
the configurations of other platforms.

WARNING: Cross file does not specify strip binary, result will not be
stripped.

Fixes: e53a5299d2 ("build: support vendor specific ARM cross builds")
Cc: stable@dpdk.org
Signed-off-by: Gavin Hu <gavin.hu@arm.com>
Reviewed-by: Phil Yang <phil.yang@arm.com>
Reviewed-by: Song Zhu <song.zhu@arm.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Jerin Jacob <jerin.jacob@caviumnetworks.com>
Tested-by: Ali Alnubani <alialnu@mellanox.com>