bus: ti-sysc: Fix warnings for unbind for serial

bus: ti-sysc: Fix warnings for unbind for serial

We can get "failed to disable" clock_unprepare warnings on unbind at least
for the serial console device if the unbind is done before the device has
been idled.

As some devices are using deferred idle, we must check the status for
pending idle work to idle the device.

Fixes: fefa31bb180d ("bus: ti-sysc: Improve handling for no-reset-on-init and no-idle-on-init")
Cc: Romain Naour <romain.naour@smile.fr>
Reviewed-by: Romain Naour <romain.naour@smile.fr>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/20220512053021.61650-1-tony@atomide.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>