usb: xhci: Use correct device for DMA map/unmap calls

xhci_unmap_td_bounce_buffer() and xhci_align_td() in xhci-ring.c
are still using the bus->controller device to perform DMA map/unmap
operations when they should instead be using bus->sysdev. This can
lead to errors since these TDs would be mapped using a different
device than the rest of the driver.

Change-Id: If55d4e8b18d2d731159518fe6c53521ea75a2315
Fixes: 4c39d4b949d3 ("usb: xhci: use bus->sysdev for DMA configuration")
Signed-off-by: Jack Pham <jackp@codeaurora.org>