usb: musb: blackfin: fix typo in new bfin_musb_vbus_status func

The common code has a "get" in the middle, but each implementation
does not have it.

Cc: stable@kernel.org
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>