net: app: client: fix local port byte-order in bind_local()

The port parameter passed to _net_app_set_local_addr() is converted
from host byte-order to network byte-order.  Here we are passing
a port value which has already been translated to network byte-order.

Let's translate the local port to host byte-order when passing it
to _net_app_set_local_addr() to fix this issue.

Signed-off-by: Michael Scott <michael@opensourcefoundries.com>