usb: fotg210-hcd: remove casting dma_alloc_coherent

Remove casting the values returned by dma_alloc_coherent.

Signed-off-by: Xu Wang <vulab@iscas.ac.cn>
Link: https://lore.kernel.org/r/20201120083054.8973-1-vulab@iscas.ac.cn


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>