Revert "Use zram->lock to protect zram_free_page() in swap free notify patch"

This reverts commit ab7df5b92546509acf751d47df3712d7fb60d842.
Revert "Staging: Fixes string split across lines in zram"

This reverts commit df96cef0800c50db58eb933106484300c9f1b6f2.
Revert "zram: fix warning of print format"

This reverts commit 45bf77ad318abd7e03b697c5a8a39d7f30e338e1.