UPSTREAM: binderfs: kill_litter_super() before cleanup

Al pointed out that first calling kill_litter_super() before cleaning up
info is more correct since destroying info doesn't depend on the state of
the dentries and inodes. That the opposite remains true is not guaranteed.

Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Christian Brauner <christian@brauner.io>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Bug: 136497735
(cherry picked from commit 4198479524aeccaf53c3a4cc73784982535573fa)
Change-Id: Ie2dfc2c2f17dde25b4215853b05fa8f21fb6b298
Signed-off-by: Hridya Valsaraju <hridya@google.com>