soc: fsl: cpm1: qmc: Split Tx and Rx TSA entries setup

The Tx and Rx entries for a given channel are set in one function.

In order to modify Rx entries and Tx entries independently of one other,
split this function in one for the Rx part and one for the Tx part.

Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Link: https://lore.kernel.org/r/20231205152116.122512-14-herve.codina@bootlin.com