rtc-cmos probe() cleanup

rtc-cmos probe() cleanup

Some cleanups for the rtc-cmos probe logic:

 - Claim i/o ports with request_region() not request_resource(),
   for better coexistence betwen platform and pnp bus glues.

 - Claim those ports earlier, to help work around procfs bugs
   (it allows duplicate names, like /proc/driver/rtc).

 - Fix some glitches in cleanup code, notably a cut'n'paste-o
   where the i/o port region might not get released during
   cleanup after a probe fault.

And some comment clarifications, including noting that this code
must work with PNPBIOS not just PNPACPI..

[[email protected]: coding-style fixes]
Signed-off-by: David Brownell <[email protected]>
Cc: Russell King <[email protected]>
Cc: Alessandro Zummo <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>