i2c: add Brendan's email to header

Signed-off-by: Thomas Ingleby <thomas.c.ingleby@intel.com>
i2c: internal structure to mraa_internal_types

* For use in hooks

Signed-off-by: Thomas Ingleby <thomas.c.ingleby@intel.com>
i2c: add init(pre-post) hooks

Signed-off-by: Thomas Ingleby <thomas.c.ingleby@intel.com>
intel_galile_rev_g: make gpio on i2c pins go hiz

Signed-off-by: Thomas Ingleby <thomas.c.ingleby@intel.com>