Revert "msm: pm: Add API to enable/disable retention mode"

This reverts commit 33ada0db9c86707097a4a51519fb25d7eadb0340.

Change-Id: Ie8d14ca975a281dc2e2c8b36118d800696859c44
Merge "Revert "msm: pm: Add API to enable/disable retention mode"" into jb4.2