usb: mtk-xhci: Do not explicitly set the DMA mask

The mtk-xhci platform glue sets the DMA mask to 32 bits on its own,
which was needed before commit fda182d ("usb: xhci: configure
32-bit DMA if the controller does not support 64-bit DMA"), but now it
has no effect, because xhci_gen_setup() sets it up for us according to
hardware capabilities. Remove the useless code.

Signed-off-by: Tomasz Figa <tfiga@chromium.org>
Link: https://lore.kernel.org/r/20191219093954.163417-1-tfiga@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/xhci-mtk.c

@@ -488,11 +488,6 @@ static int xhci_mtk_probe(struct platform_device *pdev)
 		goto disable_clk;
 	}
 
-	/* Initialize dma_mask and coherent_dma_mask to 32-bits */
-	ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
-	if (ret)
-		goto disable_clk;
-
 	hcd = usb_create_hcd(driver, dev, dev_name(dev));
 	if (!hcd) {
 		ret = -ENOMEM;