pwm: tegra: add pwm based pmc soft led blink driver

pwm: tegra: add pwm based pmc soft led blink driver

In T210b01 LED breathing(soft led blink) functionality
added and led breathing control is through PWM signal,
add pwm based driver to configure tegar pmc led breathing
parameters.

Bug 1825451

Change-Id: Id01a96a2b277fb8545ca1ee22822c576c7a4acea
Signed-off-by: Venkat Reddy Talla <vreddytalla@nvidia.com>
Reviewed-on: http://git-master/r/1467403
Reviewed-by: svccoveritychecker <svccoveritychecker@nvidia.com>
GVS: Gerrit_Virtual_Submit
Reviewed-by: Laxman Dewangan <ldewangan@nvidia.com>
(cherry picked from commit 0ad18f000ed0ccfa4dd0246ddc57e721cac42bc9)