counter: ftm-quaddec: Add const qualifier for actions_list array

The struct counter_synapse actions_list member expects a const enum
counter_synapse_action array. This patch adds the const qualifier to the
ftm_quaddec_synapse_actions to match actions_list.

Cc: Patrick Havelange <patrick.havelange@essensium.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Link: https://lore.kernel.org/r/db1df2021efb1b98e6d1a50787be5a52a1896574.1623201081.git.vilhelm.gray@gmail.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/counter/ftm-quaddec.c

@@ -162,7 +162,7 @@ enum ftm_quaddec_synapse_action {
 	FTM_QUADDEC_SYNAPSE_ACTION_BOTH_EDGES,
 };
 
-static enum counter_synapse_action ftm_quaddec_synapse_actions[] = {
+static const enum counter_synapse_action ftm_quaddec_synapse_actions[] = {
 	[FTM_QUADDEC_SYNAPSE_ACTION_BOTH_EDGES] =
 	COUNTER_SYNAPSE_ACTION_BOTH_EDGES
 };