bcachefs: Fix strndup_user() error checking

strndup_user() returns an error pointer, not NULL.

Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet 2023-09-20 01:19:53 -04:00
commit 97ecc23632