compat: backport rename of led_brightness_set() to led_set_brightness()

compat: backport rename of led_brightness_set() to led_set_brightness()

This backports this commit from linux-next:

commit 959d62fa865d2e616b61a509e1cc5b88741f065e
Author: Shuah Khan <shuahkhan@gmail.com>
Date:   Thu Jun 14 04:34:30 2012 +0800

    leds: Rename led_brightness_set() to led_set_brightness()

    Rename leds external interface led_brightness_set() to led_set_brightness().
    This is the second phase of the change to reduce confusion between the
    leds internal and external interfaces that set brightness. With this change,
    now the external interface is led_set_brightness(). The first phase renamed
    the internal interface led_set_brightness() to __led_set_brightness().
    There are no changes to the interface implementations.

    Signed-off-by: Shuah Khan <shuahkhan@gmail.com>
    Signed-off-by: Bryan Wu <bryan.wu@canonical.com>
Signed-off-by: Luis R. Rodriguez <mcgrof@frijolero.org>