of: dynamic: Constify parameter in of_changeset_add_prop_string_array()

The str_array parameter has no reason to be an un-const array.
Indeed, elements of the 'str_array' array are not changed by the code.

Constify the 'str_array' array parameter.
With this const qualifier added, the following construction is allowed:
  static const char * const tab_str[] = { "string1", "string2" };
  of_changeset_add_prop_string_array(..., tab_str, ARRAY_SIZE(tab_str));

Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Link: https://lore.kernel.org/r/20240527161450.326615-14-herve.codina@bootlin.com
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>

drivers/of/dynamic.c

@@ -984,7 +984,7 @@ EXPORT_SYMBOL_GPL(of_changeset_add_prop_string);
 int of_changeset_add_prop_string_array(struct of_changeset *ocs,
 				       struct device_node *np,
 				       const char *prop_name,
-				       const char **str_array, size_t sz)
+				       const char * const *str_array, size_t sz)
 {
 	struct property prop;
 	int i, ret;

include/linux/of.h

@@ -1639,7 +1639,7 @@ int of_changeset_add_prop_string(struct of_changeset *ocs,
 int of_changeset_add_prop_string_array(struct of_changeset *ocs,
 				       struct device_node *np,
 				       const char *prop_name,
-				       const char **str_array, size_t sz);
+				       const char * const *str_array, size_t sz);
 int of_changeset_add_prop_u32_array(struct of_changeset *ocs,
 				    struct device_node *np,
 				    const char *prop_name,