OMAP: hsmmc: Move mux configuration to hsmmc.c

Moving the definition of mux setting API from devices.c to hsmmc.c
and renaming it from "omap2_mmc_mux" to "omap_hsmmc_mux".
Also calling "omap_hsmmc_mux" from omap2_hsmmc_init.

Signed-off-by: Kishore Kadiyala <kishore.kadiyala@ti.com>
Cc: Chris Ball <cjb@laptop.org
Cc: Tony Lindgren <tony@atomide.com
Signed-off-by: Tony Lindgren <tony@atomide.com>