mvebu pinctrl changes for v3.15

 - various cleanup and refactorization
 - add drivers for the Armada 375, 380, and 385 SoCs
 - prepare dove for SoC code moving into mach-mvebu
 - DT documentation updates
Merge tag 'tags/for-mvebu-pinctrl-3xx' into mvebu/pinctrl

Sign for-mvebu/pinctrl-3xx