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 <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Mark Brown <[e-mail]>

drivers/soc/fsl/qe/qmc.c

···
 	return qmc_chan;
 }
 
+int qmc_chan_count_phandles(struct device_node *np, const char *phandles_name)
+{
+	int count;
+
+	/* phandles are fixed args phandles with one arg */
+	count = of_count_phandle_with_args(np, phandles_name, NULL);
+	if (count < 0)
+		return count;
+
+	return count / 2;
+}
+EXPORT_SYMBOL(qmc_chan_count_phandles);
+
 struct qmc_chan *qmc_chan_get_byphandles_index(struct device_node *np,
 					       const char *phandles_name,
 					       int index)

include/soc/fsl/qe/qmc.h

···
 struct device;
 struct qmc_chan;
 
+int qmc_chan_count_phandles(struct device_node *np, const char *phandles_name);
+
 struct qmc_chan *qmc_chan_get_byphandles_index(struct device_node *np,
 					       const char *phandles_name,
 					       int index);