[PATCH][next] leds: Avoid -Wflex-array-member-not-at-end warning

["Gustavo A. R. Silva" <gustavoars@kernel.org>]

-Wflex-array-member-not-at-end was introduced in GCC-14, and we are
getting ready to enable it, globally.

Use the `DEFINE_RAW_FLEX()` helper for an on-stack definition of
a flexible structure where the size of the flexible-array member
is known at compile-time, and refactor the rest of the code,
accordingly.

So, with these changes, fix the following warning:

drivers/leds/leds-cros_ec.c:70:40: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
 drivers/leds/leds-cros_ec.c | 26 +++++++++++---------------
 1 file changed, 11 insertions(+), 15 deletions(-)

diff --git a/drivers/leds/leds-cros_ec.c b/drivers/leds/leds-cros_ec.c
index 275522b81ea5..6eab0474f52d 100644
--- a/drivers/leds/leds-cros_ec.c
+++ b/drivers/leds/leds-cros_ec.c
@@ -66,24 +66,20 @@ static int cros_ec_led_send_cmd(struct cros_ec_device *cros_ec,
 				union cros_ec_led_cmd_data *arg)
 {
 	int ret;
-	struct {
-		struct cros_ec_command msg;
-		union cros_ec_led_cmd_data data;
-	} __packed buf = {
-		.msg = {
-			.version = 1,
-			.command = EC_CMD_LED_CONTROL,
-			.insize  = sizeof(arg->resp),
-			.outsize = sizeof(arg->req),
-		},
-		.data.req = arg->req
-	};
-
-	ret = cros_ec_cmd_xfer_status(cros_ec, &buf.msg);
+	DEFINE_RAW_FLEX(struct cros_ec_command, msg, data,
+			sizeof(union cros_ec_led_cmd_data));
+
+	msg->version = 1;
+	msg->command = EC_CMD_LED_CONTROL;
+	msg->insize  = sizeof(arg->resp);
+	msg->outsize = sizeof(arg->req);
+	*(struct ec_params_led_control *)msg->data = arg->req;
+
+	ret = cros_ec_cmd_xfer_status(cros_ec, msg);
 	if (ret < 0)
 		return ret;
 
-	arg->resp = buf.data.resp;
+	arg->resp = *(struct ec_response_led_control *)msg->data;
 
 	return 0;
 }
-- 
2.43.0