USB: musb: davinci dm355 updates (remainder)

Finish merging updates for DM355 chips into musb/davinci.c now
that its support is in mainline:  kick in new DRVVBUS controls.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>