Add PinTupleInterface and implement Pinset
Merge remote-tracking branch 'upstream/pinset' into lcd_hd44780
lcd_hd44780: Fix a comment to refer to data delay in the low-voltage case.
pinset: Add const qualifier to fix compilation.

Also fixed the pinset test.
tests: Fix reg_start in port test.
lcd_hd44780: Convert to use a Pinset.