reserve_stack(): switch to __nd_alloc_stack()

expand the call of nd_alloc_stack() into it (and don't
recheck the depth on the second call)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2020-03-03 11:25:31 -05:00
commit 4542576b79