s390/ap: rename and clarify ap state machine related stuff

s390/ap: rename and clarify ap state machine related stuff

There is a state machine held for each ap queue device.
The states and functions related to this where somethimes
noted with _sm_ somethimes without. This patch clarifies
and renames all the ap queue state machine related functions,
enums and defines to have a _sm_ in the name.

There is no functional change coming with this patch - it's
only beautifying code.

Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>