gpio: 3 minor tweaks

this patchset does:

1 - drops gpio_set_high, gpio_set_low from the nsc_gpio_ops vtable. While we can't drop them from scx200_gpio (or can we ?), vtable users (ie new users) dont need them, they can just use gpio_set()

2 - pure cosmetics - lose needless newlines.

3 - rename EXPORTed gpio vtables from {scx200,pc8736x}_access to _gpio_ops new name is much closer to the vtable-name struct nsc_gpio_ops, and should be clearer. Also rename the _fops vtable vars to _fileops to better disambiguate it from the gpio vtables.