DMA-API: net: brocade/bna/bnad.c: fix 32-bit DMA mask handling

The fallback to 32-bit DMA mask is rather odd:
	if (!dma_set_mask(&pdev->dev, DMA_BIT_MASK(64)) &&
	    !dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(64))) {
		*using_dac = true;
	} else {
		err = dma_set_mask(&pdev->dev, DMA_BIT_MASK(32));
		if (err) {
			err = dma_set_coherent_mask(&pdev->dev,
						    DMA_BIT_MASK(32));
			if (err)
				goto release_regions;
		}

This means we only try and set the coherent DMA mask if we failed to
set a 32-bit DMA mask, and only if both fail do we fail the driver.
Adjust this so that if either setting fails, we fail the driver - and
thereby end up properly setting both the DMA mask and the coherent
DMA mask in the fallback case.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>