arm64: dts: ti: Add PWM overlay for AM69 SK

commit 09b8ea021b9b9581a5b94d27fbd59035025e7793 from
git://git.ti.com/ti-linux-kernel/ti-linux-kernel.git



The AM69 SK has PWM output pins connected to its RPi headers on
J27 Connector. This overlay will set the appropriate pinmux and
enable PWM on those pins.

Signed-off-by: Dasnavis Sabiya <sabiya.d@ti.com>
Signed-off-by: Xulin Sun <xulin.sun@windriver.com>