Revert "blk-mq: fix potential io hang by wrong 'wake_batch'"

This reverts commit 931bd675 which is
commit 4f1731df upstream.

It breaks the Android ABI and can be brought back in an abi-safe way in
the future if it is still needed.

Bug: 161946584
Change-Id: I131cbca13e9472d8d8157b64700e1a3db8006ae5
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>