boost: put back chrono select for coroutine

boost: put back chrono select for coroutine

coroutine module does use chrono directly:

./libs/coroutine/performance/asymmetric/segmented/Jamfile.v2: <library>/boost/chrono//boost_chrono
./libs/coroutine/performance/asymmetric/Jamfile.v2: <library>/boost/chrono//boost_chrono
./libs/coroutine/performance/symmetric/segmented/Jamfile.v2: <library>/boost/chrono//boost_chrono
./libs/coroutine/performance/symmetric/Jamfile.v2: <library>/boost/chrono//boost_chrono

So put back select of chrono for coroutine

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>