dt-bindings: clock: ehrpwm: Add support for AM64 specific compatible

Introduce AM64 specific compatible for epwm time-base sub-module clock.

Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Link: https://lore.kernel.org/r/20210528045743.16537-2-lokeshvutla@ti.com


Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Tero Kristo <kristo@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>