Make omap2 FS USB code use new mux functions. Do not mux usb2_tllse0
as it has multiple options.

Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NTony Lindgren <tony@atomide.com>

Looks like this code was only working on boards that had
the usb_l4_ick enabled in the bootloader.
Signed-off-by: NTony Lindgren <tony@atomide.com>

Move omap2 FS USB platform init code into mach-omap2/usb-fs.c. This will
allow further work later on to use omap hwmod for initializing the
device.

Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NTony Lindgren <tony@atomide.com>