malloc: make free list removal function public

malloc: make free list removal function public

We will need to be able to remove entries from free lists from
heaps during certain events, such as rollbacks, or when freeing
memory to the system (where a previously element disappears and
thus can no longer be in the free list).

Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
Tested-by: Santosh Shukla <santosh.shukla@caviumnetworks.com>
Tested-by: Hemant Agrawal <hemant.agrawal@nxp.com>
Tested-by: Gowrishankar Muthukrishnan <gowrishankar.m@linux.vnet.ibm.com>