sata_promise: other cleanups

Minor coding-style fixes for sata_promise:
- remove stray blank lines
- fix checkpatch.pl errors; warnings about long lines
  remain, but I don't intend to address those at this time
- remove two inline directives: neither is essential and
  both functions are trivially inlinable anyway by virtue
  of being static and having a single unique call site
- fix comment in pdc_interrupt(): the bits in PDC_INT_SEQMASK
  denote SEQIDs not tags, the distinction becomes important
  when NCQ gets implemented

Signed-off-by: Mikael Pettersson <mikpe@it.uu.se>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>