PNP: Clean up coding style in pnp.h

Address the following checkpatch complaints:

ERROR: "foo * bar" should be "foo *bar"
ERROR: space required after that ';' (ctx:VxV)

Signed-off-by: GuoHua Cheng <chenguohua@jari.cn>
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>