drm/exynos: dp: Use correct module license

According to the header comment in the source file, the driver is
licensed under GPL v2, so update MODULE_LICENSE() to match that.
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NInki Dae <inki.dae@samsung.com>

drivers/gpu/drm/exynos/exynos_dp_core.c

@@ -1390,4 +1390,4 @@ struct platform_driver dp_driver = {
 
 MODULE_AUTHOR("Jingoo Han <jg1.han@samsung.com>");
 MODULE_DESCRIPTION("Samsung SoC DP Driver");
-MODULE_LICENSE("GPL");
+MODULE_LICENSE("GPL v2");