xhci: dbc: Don't use xhci_write_64() as it takes xhci as a parameter

xhci_write_64() is essentially a wrapper for lo_hi_writeq(), but it
requires struct xhci_hcd * as a parameter.
Use lo_hi_writeq() directly instead

No functional changes
This change helps decoupling xhci and DbC

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20200723144530.9992-10-mathias.nyman@linux.intel.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>