[Spectrum Virtualize Family] During HyperSwap create volume
there is multiple lsmdiskgrp calls, which is causing more
concurrent calls on SVC.
This patch fixes the issue by caching the site information during
initialization and checking for HyperSwap pool site information.
Closes-Bug: #1917605
Change-Id: I3f734e55efeabcfdeca4c4f3e87bc4a5a0481875
