platform/chrome: lightbar: Use flexible array member

Variable arrays should be defined as [], not [0], otherwise
the kernel complains:

memcpy  : detected field-spanning write (size 9) of single field "param->set_program_ex.data" at drivers/platform/chrome/cros_ec_lightbar.c:603 (size 0)

Fixes: 9600b8b ("platform/chrome: lightbar: Add support for large sequence")
Signed-off-by: Gwendal Grignou <gwendal@google.com>
Link: https://lore.kernel.org/r/20260204034848.697033-1-gwendal@google.com
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>

Author: gwendalcr

include/linux/platform_data/cros_ec_commands.h

@@ -2028,7 +2028,7 @@ struct lightbar_program {
 struct lightbar_program_ex {
 	uint8_t size;
 	uint16_t offset;
-	uint8_t data[0];
+	uint8_t data[];
 } __ec_todo_packed;
 
 struct ec_params_lightbar {