atomic: fix atomic_add_unless() fallback's return value
According to the kernel documentation:
Returns non-zero if
@u, and zero otherwise.
[Eric: fix its callers to maintain current behaviour]
Signed-off-by: Eric Engestrom <email@example.com>
The intel part of this patch looks like a big change, but if you remove all the whitespace, it's simply returning when it would've gone into the branch, thereby reversing it.