ARM: davinci: da850: add EHRPWM & ECAP DT node

Add da850 EHRPWM & ECAP DT node along with pin-mux details.
Also adds OF_DEV_AUXDATA for EHRPWM & ECAP driver to use EHRPWM & ECAP
clock.

Signed-off-by: Philip Avinash <avinashphilip@ti.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>