omap2+: Allow hwmod state changes to mux pads based on the state changes

Allow hwmod state changes to mux pads based on the state changes.

By default, only enable and disable the pads. In some rare cases
dynamic remuxing for the idles states is needed, this can be done
by passing the enable, idle, and off pads from board-*.c file along
with OMAP_DEVICE_PAD_REMUX flag.

Thanks to Paul Walmsley <paul@booyaka.com> for the comments on the
hwmod related changes.

Signed-off-by: Tony Lindgren <tony@atomide.com>