davinci: Add DA830/OMAP-L137 EVM specific pinmux setting for McASP1

The DA830/OMAP-L137 EVM cannot use the default pinmux setup for McASP1
so put the correct settings in the board file for that platform.

Signed-off-by: Mark A. Greer <mgreer@mvista.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>