selftests: timers: Remove unneeded semicolon

Remove unnecessary semicolons reported by Coccinelle/coccicheck and the
semantic patch at scripts/coccinelle/misc/semicolon.cocci.

Signed-off-by: Chen Ni <nichen@iscas.ac.cn>
Acked-by: John Stultz <jstultz@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>