doc: announce API change for sched library
doc: announce API change for sched library

There will be change in API functions because of mbuf sched field
updates, outlined in deprecation note of mbuf->hash.sched.

Signed-off-by: Jasvinder Singh <97b766ecf460b59e2781d4fc0469065206870f5c@intel.com>
Acked-by: Cristian Dumitrescu <25468b8a3698eeb3c368247f8635924bb4a1ce2c@intel.com>
Acked-by: Reshma Pattan <4d9eb35579760ed1c2db754a6b402039c9c8a1cb@intel.com>
Acked-by: Mohammad Abdul Awal <38374f06acadb758f6fbf72e9fd35fff1cac6ad2@intel.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk