net: cnss_prealloc: add pre alloc support for socket buffer

The cnss wlan module which has interfaced with high latency
bus(e.g. SDIO) needs physical contiguous memory more than
one page for its socket buffer initialization. If the system
memory has high fragmented it’s not possible to get this much
huge physically contiguous memory through dynamic memory
allocation and will create the wlan driver load, socket descriptor
initiation, scanning and connection failure for the cnss wlan module.

This feature enable socket buffer to use pre allocated memory
for socket buffer initialization and release it to back to
pre-allocated pool.

CRs-Fixed: 1023094
Change-Id: I1cf730cc06096f4b2ab21b4e1dbf3e94d988630e
Signed-off-by: Sarada Prasanna Garnayak <sgarna@codeaurora.org>