malloc: fix allocation of almost hugepage size

malloc: fix allocation of almost hugepage size

If called to allocate memory of size is between multiple of hugepage
size minus malloc_header_len and hugepage size, rte_malloc fails.

This fix replaces malloc_elem_trailer_len with malloc_elem_overhead in
try_expand_heap() to include malloc_elem_header_len when calculating
n_seg.

Bugzilla ID: 800
Fixes: 07dcbfe0101f ("malloc: support multiprocess memory hotplug")
Cc: stable@dpdk.org
Signed-off-by: Fidaullah Noonari <fidaullah.noonari@emumba.com>
Acked-by: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>