oeqa/runtime : add test for RTC(Real Time Clock)

This test is checking the functionality of the RTC(Real Time Clock). The Check_if_RTC_(Real_Time_Clock)_can_work_correctly manual test case from oeqa/manual/bsp-hw can be replace by this runtime test.

Signed-off-by: Teoh Jay Shen <jay.shen.teoh@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>