Revert "fs: fix missing declaration of init_files"

This reverts commit 62861a5d which is
commit 2b2fc0be upstream.

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

Bug: 161946584
Change-Id: Icff4928c0dcd4650849d647cdb493d24875d62f9
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>