nptl: Use a single loop in pthread_cond_wait instaed of a nested loop

nptl: Use a single loop in pthread_cond_wait instaed of a nested loop

The loop was a little more complicated than necessary. There was only one
break statement out of the inner loop, and the outer loop was nearly empty.
So just remove the outer loop, moving its code to the one break statement in
the inner loop. This allows us to replace all gotos with break statements.

Signed-off-by: Malte Skarupke <malteskarupke@fastmail.fm>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
(cherry picked from commit 929a4764ac90382616b6a21f099192b2475da674)