davinci: da8xx/omapl EVM: Specify reserved channels/slots

The drivers on da8xx/omapl EVMs do not utilize all the channels
and slots provided by EDMA. Some of these are better utilitzed by
the DSP on the SoC for speeding up codec operations.

Reserve these channels/slots for the DSP.

Signed-off-by: Sudhakar Rajashekhara <sudhakar.raj@ti.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>