sensor_i2c/hi3516cv300: declare MODULE_LICENSE("GPL")

User-reported failure on real hi3516cv300 hardware (IMX323 over I2C,
OpenIPC 2.6.04.28-lite):

  open_sensor_i2c: Unknown symbol i2c_new_device (err 0)
  open_sensor_i2c: Unknown symbol i2c_unregister_device (err 0)

The kernel's `i2c_new_device` / `i2c_unregister_device` are
`EXPORT_SYMBOL_GPL`. With no `MODULE_LICENSE` in this module, the
kernel treats it as proprietary and refuses to resolve those symbols.

The cv300 sensor_i2c module was added in #38 (commit 20882c6) without
module init/exit boilerplate or license declaration — it was a
half-port of the vendor's combined `hi3516cv300_sensor.ko`, where the
top-level wrapper would have lived. Sensor_spi (split out by the same
port) doesn't hit this because all the helpers it calls (ioremap_nocache,
iounmap, …) are non-GPL exports, and the recent #59 added `EXPORT_SYMBOL`
for ssp_drv_*. The i2c branch of i2c_drv.c hits two GPL-only symbols
that have always required this license tag.

Verified live on hi3516cv300 hardware (172.17.32.126) reproducing the
user's `Unknown symbol i2c_new_device` failure. Building this fix and
testing on the same camera confirms `open_sensor_i2c.ko` loads cleanly
once the license tag is in place (combined with the firmware-side fix
in OpenIPC/firmware#2030 that ships and pre-loads sensor_spi for cv300).

A proper module_init / module_exit / module_param wrapper for cv300
sensor_i2c is a separate, larger piece of work — not addressed here.
The .ko's load-time symbol resolution is what blocks the camera; once
that succeeds, the symbols inside (i2c_drv_init etc.) are reachable
through the existing in-kernel callback mechanism, same as before.

Refs #62, #66.

Author: Vixand

kernel/sensor_i2c/hi3516cv300/sensor.c

@@ -1,3 +1,5 @@
+#include <linux/module.h>
+
 #include "hi_osal.h"
 
 #include "sensor.h"
@@ -133,3 +135,9 @@ HI_VOID sensor_dev_exit(HI_S32 s32SensorIndex)
     osal_printk("sensor dev exit OK.\n");
 	g_stSensorDev[s32SensorIndex] = NULL;
 }
+
+/* The kernel's i2c_new_device / i2c_unregister_device are EXPORT_SYMBOL_GPL,
+ * so this module must declare a GPL-compatible license or insmod fails with
+ * "Unknown symbol" on those calls in i2c_drv_init / i2c_drv_exit.
+ */
+MODULE_LICENSE("GPL");