usb: musb: cppi_dma: export cppi_interrupt()

commit 8b416b0b25d5d8ddb3a91c1d20e1373582c50405 upstream.

Now that DaVinci glue layer can be modular, we must export cppi_interrupt()
that it may call...

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>