soc: fsl: cpm1: qmc: Handle timeslot entries at channel start() and stop()

In order to support runtime timeslot route changes, enable the
channel timeslot entries at channel start() and disable them at
channel stop().

Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Link: https://lore.kernel.org/r/20231205152116.122512-16-herve.codina@bootlin.com