ovn pinctrl: Pass 'struct rconn *swconn' to all the functions which u…

…se 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 <[email protected]>
Acked-by: Mark Michelson <[email protected]>
Signed-off-by: Numan Siddique <[email protected]>
Signed-off-by: Ben Pfaff <[email protected]>