davinci: Change DA8xx/OMAP-L13x McASP registration routine name

For consistency with existing code, change the name of
da8xx_init_mcasp() to da8xx_register_mcasp().

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