debugfs: call debugfs_real_fops() only after debugfs_file_get()

The current implementation of debugfs_real_fops() relies on a
debugfs_fsdata instance to be installed at ->d_fsdata.

With future patches introducing lazy allocation of these, this requirement
will be guaranteed to be fullfilled only inbetween a
debugfs_file_get()/debugfs_file_put() pair.

The full proxies' fops implemented by debugfs happen to be the only
offenders. Fix them up by moving their debugfs_real_fops() calls past those
to debugfs_file_get().

full_proxy_release() is special as it doesn't invoke debugfs_file_get() at
all. Leave it alone for now.

Change-Id: I77c899614d317a581dea72c96583cd9f55f97930
Signed-off-by: Nicolai Stange <nicstange@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Git-commit: 154b9d7512ae012aca7b4e90af67a72419ad1941
Git-repo: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: Tingwei Zhang <tingwei@codeaurora.org>