xen: credit2: tidy up functions names by removing leading '__'.

xen: credit2: tidy up functions names by removing leading '__'.

There is no reason for having pretty much all of the
functions whose names begin with double underscores
('__') to actually look like that.

In fact, that is misleading and makes the code hard
to read and understand. So, remove the '__'-s.

The only two that we keep are __runq_assign() and
__runq_deassign() (althought they're converted to
single underscore). In fact, in those cases, it is
indeed useful to have those sort of a "raw" variants.

In case of __runq_insert(), which is only called
once, by runq_insert(), merge the two functions.

No functional change intended.

Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com>
Acked-by: George Dunlap <george.dunlap@citrix.com>