clk: qcom: gcc-sdm660: Add MODULE_LICENSE

Add a module license to match the license at the top of this file and
silence a build warning.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
diff --git a/drivers/clk/qcom/gcc-sdm660.c b/drivers/clk/qcom/gcc-sdm660.c
index b5f1e8f..ba239ea 100644
--- a/drivers/clk/qcom/gcc-sdm660.c
+++ b/drivers/clk/qcom/gcc-sdm660.c
@@ -2476,4 +2476,5 @@ static void __exit gcc_sdm660_exit(void)
 }
 module_exit(gcc_sdm660_exit);
 
+MODULE_LICENSE("GPL v2");
 MODULE_DESCRIPTION("QCOM GCC sdm660 Driver");