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.com


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>