usb: xhci: factor out roothub bandwidth cleanup

usb: xhci: factor out roothub bandwidth cleanup

Introduce xhci_rh_bw_cleanup() to release all bandwidth tracking
structures associated with xHCI roothub ports.

The new helper clears:
 * TT bandwidth entries
 * Per-interval endpoint lists

This refactors and consolidates the existing per-port cleanup logic
previously embedded in xhci_mem_cleanup(), reducing duplication and
making the teardown sequence easier to follow.

The helper will also be reused for upcoming S4 resume handling.

Signed-off-by: Niklas Neronin <niklas.neronin@linux.intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://patch.msgid.link/20260402131342.2628648-7-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>