usb: musb: introduce DA8xx/OMAP-L1x glue layer

Texas Instruments DA8xx/OMAP-L1x glue layer for the
MUSBMHRDC driver.

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Yadviga Grigorieva <yadviga@ru.mvista.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>