Use DECLARE_FLEX_ARRAY() helper in drivers/i2c/i2c-core-acpi.c

[GustavoARSilva]

diff -u -p ./drivers/i2c/i2c-core-acpi.c /tmp/nothing/drivers/i2c/i2c-core-acpi.c
--- ./drivers/i2c/i2c-core-acpi.c
+++ /tmp/nothing/drivers/i2c/i2c-core-acpi.c
@@ -26,7 +26,6 @@ struct gsb_buffer {
        union {
                u16     wdata;
                u8      bdata;
-               u8      data[0];
        };
 } __packed;