soc: fsl: cpm1: qmc: Introduce qmc_chan_count_phandles()

No function in the QMC API is available to get the number of phandles
present in a phandle list.

Fill this lack introducing qmc_chan_count_phandles().

Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Link: https://patch.msgid.link/20240701113038.55144-9-herve.codina@bootlin.com


Signed-off-by: Mark Brown <broonie@kernel.org>