MFC r349579: nctgpio: change default pin names to those used by the datasheet(s)

That is, instead of the current GPIO00 - GPIO15 the names will be GPIO00
- GPIO07, GPIO10 - GPIO17. The first digit is a GPIO "bank" / group
number and the second one is a pin number within the bank. Alternative
view is that the pin names are changed from decimal numbering scheme to
octal one (as there are 8 pins per bank).

MFC r327502:

nctgpio: add new device id for the GPIO chip in PCEngines APU3

PR: 224512
Submitted by: mike@sentex.net

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

nctgpio(4): Don't index past the end of sc->pins array

This driver thinks that the NCT_MAX_PIN index is a valid index in a few places
(nct_attach() for-loop, as well as NCT_IS_VALID_PIN()). Allocate room for
NCT_MAX_PIN as an index, that is, NCT_MAX_PIN + 1 elements.

Reported by: Coverity
CIDs: 1353806, 1353807, 1353808, 1353809, 1353810
Sponsored by: EMC / Isilon Storage Division

sys/dev: use our nitems() macro when it is avaliable through param.h.

No functional change, only trivial cases are done in this sweep,
Drivers that can get further enhancements will be done independently.

Discussed in: freebsd-current

Add support for the Nuvoton NCT5104D.

Make it compile only for i386/amd64 for now as it's been tested there.
It's quite possible it'll show up elsewhere and we can enable it
for other architectures later.

Tested:

* PC Engines APU1C4

Submitted by: Daniel Wyatt <daniel@dewyatt.com>
Reviewed by: adrian, loos
Differential Revision: https://reviews.freebsd.org/D5389