linux-next: build failure after merge of the rtc tree

Hi all,

After merging the rtc tree, today's linux-next build (arm
multi_v7_defconfig) failed like this:

ERROR: modpost: missing MODULE_LICENSE() in drivers/rtc/lib_test.o

Caused by commit

  1d1bb12a8b18 ("rtc: Improve performance of rtc_time64_to_tm(). Add tests.")

I have used the rtc tree from next-20210809 for today.

-- 
Cheers,
Stephen Rothwell