mm: swap: Add randomization check for swapon/off calls

Add addtional check on swapon/swapoff sycalls to disable
randomization of swap offsets if GENHD_FL_NO_RANDOMIZE
flag is passed.

Change-Id: I6f5ce7275f09b812a8954328331545eee0aa77ef
Signed-off-by: Vivek Kumar <vivekuma@codeaurora.org>