usb: musb: disable OTG AUTOIDLE only with omap3430

Omap3 MUSB AUTOIDLE functionality configured through OTG_SYSCONFIG
register prevents the device from going into retention.
This is a workaround (by Richard Woodruff/TI), as his comment :
> A new MUSB bug which is a match to data below was identified very
> recently (on hardware and in simulation).
> This bug is in 3430 and not 3630.
> As a priority test (and as new default) you should have engineers
> disable autoidle for MUSB block.
> This is the workaround which will show up in next errata.

Signed-off-by: Niilo Minkkinen <ext-niilo.1.minkkinen@nokia.com>
Signed-off-by: Richard Woodruff <r-woodruff2@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>