ovn pinctrl: Pass 'struct rconn *swconn' to all the functions which use it

ovn pinctrl: Pass 'struct rconn *swconn' to all the functions which use it

In pinctrl.c, many functions use 'swconn' variable which is declared as
global static. This patch passes 'swconn' as a variable to functions.
This will help in an upcoming patch which makes processing
packet-ins in a separate pthread.

Suggested-by: Mark Michelson <mmichels@redhat.com>
Acked-by: Mark Michelson <mmichels@redhat.com>
Signed-off-by: Numan Siddique <nusiddiq@redhat.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>