linux-generic: rwlock: fix odp_rwlock_read_trylock()
linux-generic: rwlock: fix odp_rwlock_read_trylock()

odp_rwlock_read_trylock() currently works only if there are no readers
(and writers) as it compares counter with 0. Make it actually work in
case there are other active readers.

Fixes: https://bugs.linaro.org/show_bug.cgi?id=2974

Signed-off-by: Dmitry Eremin-Solenikov <05e7612c354c8479a2d1e9b11fb63ce18664b3ca@linaro.org>
Reviewed-by: Bill Fischofer <52f3c909d51cc5d355a68a403df6906b3c1a8f83@linaro.org>
Signed-off-by: Maxim Uvarov <db4d16e02ae2d7493db430203537da8b2e34f290@linaro.org>

dkrot/odp,dkrot/odp,dkrot/odp,dkrot/odp