Initial ioctl-to-sysfs migration for AVR

This commit introduces /sys/class/backlight/avr-backlight and
/sys/class/leds/avr::keypad files in sysfs while remaining
compatible with ioctl() calls.
Add keypad brightness support, removal support

Add support for 0-255 keypad led levels.
Add _remove calls for led and backlight.
Merge branch 'master' into avr_mfd
Disable lcd-backlight in msm_fb for Acer A1
Android uses LEDs infrastructure for LCD backlight

Oookay...
Switching to a common infrastructure
Switching to MFD.

Boots but hangs after bootanimation completes.
Dummy AVR driver

This driver returns OK for any ioctl calls so that Acer lights
module does not crash.
Proper initialisation, debug, cleanup

This version boots and works properly.
Fully-working LED class driver

This version removes timeout for leds so that the userspace can
decide whether keep them on or off, shuts down and restores
brightness without userspace interaction.
Add range check, set default on probe.

Also update license and rename mutex so that it looks like a proper module.
Update license and rename mutex
Merged a6d511e5155406cd214d3af3ff9cffc69548b006

Driver by NeilBrown is already included in the mainline kernel
Supply tca6506 platform data
Import 1bd465e6b0e2b559db47420fea686507a01cfab0
Import 92722b1bb1ebcba767f9c6ee499992ee33367268
Import a1dd8c617217322614f0465ae347895c4b58e1ab
Import 5ada28bf76752e33dce3d807bf0dfbe6d1b943ad
Enable TCA6507
Remove multiple LEDS_TCA6507 definitions