Revert RTC test script change

As a result of discussion here:
#1154

Author: toyowata

workspace_tools/tests.py

@@ -457,15 +457,6 @@
         "source_dir": join(TEST_DIR, "mbed", "rtc"),
         "dependencies": [MBED_LIBRARIES, TEST_MBED_LIB],
         "automated": True,
-        "mcu": ["K20D50M","TEENSY3_1","KL05Z","KL25Z","KL43Z","KL46Z","K22F","K64F","MTS_GAMBIT",
-                "MAX32600","MAX32610","DELTA_DFCM_NNN40","LPC11U6X","LPC15XX","ARCH_PRO","LPC1768",
-                "UBLOX_C027","XBED_LPC1768","LPC23XX","LPC2460","LPC408X","LPC4330","LPC4337","RZ_A1H",
-                "EFM32GG_STK3700","EFM32HG_STK3400","EFM32LG_STK3600","EFM32WG_STK3800","EFM32ZG_STK3200",
-                "NZ32ST1L","DISCO_F051R8","NUCLEO_F030R8","NUCLEO_F070RB","NUCLEO_F072RB","NUCLEO_F091RC",
-                "DISCO_F100RB","NUCLEO_F103RB","DISCO_F303VC","DISCO_F334C8","NUCLEO_F302R8","NUCLEO_F303RE",
-                "NUCLEO_F334R8","STM32F3XX","ARCH_MAX","DISCO_F401VC","DISCO_F407VG","DISCO_F429ZI",
-                "MTS_DRAGONFLY_F411RE","MTS_MDOT_F405RG","MTS_MDOT_F411RE","NUCLEO_F401RE","NUCLEO_F411RE",
-                "NUCLEO_F446RE","DISCO_L053C8","NUCLEO_L053R8","NUCLEO_L073RZ","MOTE_L152RC","NUCLEO_L152RE"],
         #"host_test": "rtc_auto",
         "duration": 15
     },