Documentation: dt: add Broadcom BCM7038 PWM controller binding

Add a binding documentation for the Broadcom BCM7038 PWM controller found in
BCM7xxx chips.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
1 file changed