omap3: cm-t35: add mux initialization

CM-T35 can be assembled with different set of peripherals thus making
certain interfaces available to user as GPIOs or dedicated pins. Because
of it CM-T35 bootloader sets up mux configuration only for pins
necessary to boot the system and the rest of the mux configuration is
done by the kernel. Besides, having mux configuration in the kernel
allows to minimize dependancy on bootloader.

Signed-off-by: Mike Rapoport <mike@compulab.co.il>
Signed-off-by: Tony Lindgren <tony@atomide.com>