davinci: Audio support for DA850/OMAP-L138 EVM

Define resources for McASP used on DA850/OMAP-L138 EVM, add platform
device defintion and Pin Mux configurations.

Signed-off-by: Chaithrika U S <chaithrika@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>