soc: fsl: cpm1: qmc: Introduce functions to change timeslots at runtime

Introduce qmc_chan_{get,set}_ts_info() function to allow timeslots
modification at runtime.

The modification is provided using qmc_chan_set_ts_info() and will be
applied on next qmc_chan_start().
qmc_chan_set_ts_info() must be called with the channel rx and/or tx
stopped.

Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Link: https://lore.kernel.org/r/20231205152116.122512-18-herve.codina@bootlin.com