xhci: move event processing for one interrupter to a separate function

xhci: move event processing for one interrupter to a separate function

Split the main XHCI interrupt handler into a different API, so that other
potential interrupters can utilize similar event ring handling.  A scenario
would be if a secondary interrupter required to skip pending events in the
event ring, which would warrant a similar set of operations.

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>
Link: https://lore.kernel.org/r/20240217001017.29969-7-quic_wcheng@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>