usb: musb: core: call dma_controller_destroy() in the err path

The cleanup in the error is missing the dma controller. The structure is
allocated at runtime and ux500 allocates even a little more than just
this struct. So cleanup!

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>