vfs: clean up argument list for vfs_create()

vfs: clean up argument list for vfs_create()

As Neil points out:

"I would be in favour of dropping the "dir" arg because it is always
d_inode(dentry->d_parent) which is stable."

...and...

"Also *every* caller of vfs_create() passes ".excl = true".  So maybe we
don't need that arg at all."

Drop both arguments from vfs_create() and fix up the callers.

Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: NeilBrown <neil@brown.name>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20251111-dir-deleg-ro-v6-9-52f3feebb2f2@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>