bone-pinmux-helper: Add support for "mode" device-tree parameter The new mode...

bone-pinmux-helper: Add support for "mode" device-tree parameter The new mode parameter is used to set the initial pinmux mode to something other than "default" or NULL, which is what happens currently. This allows enabling SoC hardware via device-tree which requires specific pinmux settings to function on boot, but still leaves the pinmux register under control of the bone-pinmux- helper driver meaning the pinmux setting can be changed at run time via user-mode access to sysfs.

Signed-off-by: Charles Steinkuehler <charles@steinkuehler.net>