tests: Increase WPS timeout to 30 seconds

tests: Increase WPS timeout to 30 seconds

Number of crypto operations seem to take very long time in the valgrind
tests (about five seconds for public key generation for M1 and M2 on a
virtual server) and this is enough to push the test runs to hit the
timeout frequently even when there is no real error. Make this less
frequent by increasing WPS test case timeout from 15 to 30 seconds to
avoid issues based on the test scripts.

Signed-hostap: Jouni Malinen <j@w1.fi>