xhci: handle failed buffer copy to URB sg list and fix a W=1 copiler warning

xhci: handle failed buffer copy to URB sg list and fix a W=1 copiler warning

[ Upstream commit 271a21d8b280b186f8cc9ca6f7151902efde9512 ]

Set the urb->actual_length to bytes successfully copied in case all bytes
weren't copied from a temporary buffer to the URB sg list.
Also print a debug message

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210617150354.1512157-4-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>