xhci: create one unified function to calculate TRB TD remainder.

xhci versions 1.0 and later report the untransferred data remaining in a
TD a bit differently than older hosts.

We used to have separate functions for these, and needed to check host
version before calling the right function.

Now Mediatek host has an additional quirk on how it uses the TD Size
field for remaining data. To prevent yet another function for calculating
remainder we instead want to make one quirk friendly unified function.

Tested-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>