fs: move inode sysctls to its own file

fs: move inode sysctls to its own file

Patch series "sysctl: 4th set of kernel/sysctl cleanups".

This is slimming down the fs uses of kernel/sysctl.c to the point that the
next step is to just get rid of the fs base directory for it and move that
elsehwere, so that next patch series starts dealing with that to demo how
we can end up cleaning up a full base directory from kernel/sysctl.c, one
at a time.

This patch (of 9):

kernel/sysctl.c is a kitchen sink where everyone leaves their dirty
dishes, this makes it very difficult to maintain.

To help with this maintenance let's start by moving sysctls to places
where they actually belong.  The proc sysctl maintainers do not want to
know what sysctl knobs you wish to add for your own piece of code, we just
care about the core logic.

So move the inode sysctls to its own file.  Since we are no longer using
this outside of fs/ remove the extern declaration of its respective proc
helper.

We use early_initcall() as it is the earliest we can use.

Link: https://lkml.kernel.org/r/20211129205548.605569-1-mcgrof@kernel.org
Link: https://lkml.kernel.org/r/20211129205548.605569-2-mcgrof@kernel.org
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Xiaoming Ni <nixiaoming@huawei.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Stephen Kitt <steve@sk2.org>
Cc: Lukas Middendorf <kernel@tuxforce.de>
Cc: Antti Palosaari <crope@iki.fi>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>