defconfig: enable fastrpc driver on Lahaina

Enable compilation of the fastrpc driver on Lahaina, which
provides a communication mechanism that allows clients to
make remote method invocations across processor boundary
to applications, compute and sensors DSP processors.

Change-Id: I2a43104e260b3e129e3447840f3180843c10ce3a
Signed-off-by: Edgar Flores <edgarf@codeaurora.org>