pwm: use local scope for register writes
pwm: use local scope for register writes

Previously, the writes would not occur until drop happened on the
register references.  This was not the order we wanted things to
happen in.  The naive approach here does the right thing.

mcoffin/zinc,richo/zinc,phil-opp/zinc,troplin/zinc,mcoffin/zinc,hackndev/zinc,troplin/zinc,posborne/zinc,ntwyman/zinc,ntwyman/zinc,farcaller/zinc,richo/zinc,posborne/zinc,posborne/zinc,hackndev/zinc,ntwyman/zinc,farcaller/zinc,hackndev/zinc,phil-opp/zinc,phil-opp/zinc,farcaller/zinc,farcaller/zinc,ntwyman/zinc,hackndev/zinc,mcoffin/zinc,mcoffin/zinc,hackndev/zinc,phil-opp/zinc,troplin/zinc,richo/zinc,mcoffin/zinc,posborne/zinc,troplin/zinc,troplin/zinc,richo/zinc,phil-opp/zinc,richo/zinc,farcaller/zinc,posborne/zinc,ntwyman/zinc