GPIO abstraction for power and host control

In libopenbmc_intf/power_gpio.c there are GPIO abstractions for power
related GPIOs.
Host control related GPIOs need to do the same abstraction.

The changes include:
1. Add host control related GPIOs in gpio_configs and update
system_manager.py
2. Update control_host_obj.c to use the abstracted GPIOs
3. Update GPIO_CONFIGS for all machines and add host control related
GPIOs

power_gpio will be renamed to gpio_configs in next commit;

Resolves openbmc/openbmc#814

Change-Id: I7832065d495d7d64c5df2f5b177005b97e68900a
Signed-off-by: Lei YU <mine260309@gmail.com>
12 files changed