soc: fsl: cpm1: qmc: Check available timeslots in qmc_check_chans()

The timeslots checked in qmc_check_chans() are the timeslots used.
With the introduction of the available timeslots, the used timeslots
are a subset of the available timeslots. The timeslots checked during
the qmc_check_chans() call should be the available ones.

Simply update and check the available timeslots instead of the used
timeslots in qmc_check_chans().

Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Link: https://lore.kernel.org/r/20231205152116.122512-12-herve.codina@bootlin.com