wanrouter: fix sparse warnings: context imbalance

Impact: Attribute functions with __acquires(...) resp. __releases(...).

Fix this sparse warnings:
  net/wanrouter/wanproc.c:82:13: warning: context imbalance in 'r_start' - wrong count at exit
  net/wanrouter/wanproc.c:103:13: warning: context imbalance in 'r_stop' - unexpected unlock
  net/wanrouter/wanmain.c:765:13: warning: context imbalance in 'lock_adapter_irq' - wrong count at exit
  net/wanrouter/wanmain.c:771:13: warning: context imbalance in 'unlock_adapter_irq' - unexpected unlock

Signed-off-by: Hannes Eder <hannes@hanneseder.net>
Signed-off-by: David S. Miller <davem@davemloft.net>