hammerhead: add charging led support

Also introduces led priority handling for
battery vs notification vs attention
(copied from jf-common).

Requires the hammerhead kernel led
always on support patch.

Change-Id: I1a2f3aae457c6d7e4e3c3f9ca39cbe42d39c3bc2
Add the CM DSP library to the device-specific effects table

Change-Id: Iec434885dc30a6623556b9c0c132fef4a0201314