usb: musb: blackfin: call usb_nop_xceiv_unregister() in musb_platform_exit()

Blackfin's musb_platform_exit() forgets to call usb_nop_xceiv_unregister().
While fixing this, also remove the unneeded blank line there.

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Cc: stable <stable@kernel.org>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>