Documentation: leds: Add description of LED Flash class extension
Documentation: leds: Add description of LED Flash class extension

The documentation being added contains overall description of the
LED Flash Class and the related sysfs attributes.

Signed-off-by: Jacek Anaszewski <6a953cb1c532e2765a42e582ecefff5a01106214@samsung.com>
Acked-by: Kyungmin Park <504c23c4986a3760712724894be3105092c27331@samsung.com>
Cc: Richard Purdie <a03894c799ea916bd571ce8f12ed88f6fb3400f7@rpsys.net>
Signed-off-by: Bryan Wu <956b36c0f472d2edb239225c10f7e4411d1efbb9@gmail.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs