linux-phytec-ti

usb: musb: host: release dma channels if no active io

Currently DMA channels are allocated and they remain allocated
even if there is no active data transfer. Added channel_release()
whenever there is no pending request.

Signed-off-by: Ajay Kumar Gupta <ajay.gupta@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>