The GPIO API was pretty clunky and pin settings were decentralized,
making it hard to see what was happening and making GPIO stuff look
like a mess, frankly.
Instead of passing clunky (port, pin) pairs everywhere, GPIOs are now
identified with a single int. The extra overhead should be minimal as
GPIO configuration is generally not on a performance-critical path.
Pin assignments are now mostly consolidated in gpio-target.h and put
in various tables so gpio_init() can assign most pins at boot time.
Most drivers no longer need to touch GPIOs and basic pin I/O stuff
can happen without config since pins are put into the right state.
IRQ pins still need to be configured manually before use.
Change-Id: Ic5326284b0b2a2f613e9e76a41cb50e24af3aa47
e85bc74b30