i3c: dw: Drop redundant Hot-Join cancel_work_sync() in shutdown

i3c: dw: Drop redundant Hot-Join cancel_work_sync() in shutdown

The I3C core now installs an i3c_bus_type shutdown callback that
flushes master->hj_work (via i3c_master_shutdown()) before any driver's
platform shutdown hook runs. The explicit cancel_work_sync() in
dw_i3c_shutdown() is therefore redundant: by the time it executes, the
Hot-Join worker has already been cancelled, and the shutting_down gate
makes a new worker a no-op.

Remove the now-unneeded call. No functional change.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260608054312.10604-6-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>