STM32L4 - Enable the low power timer

Enable the low power timer for the following targets:
 - DISCO_L476VG
 - NUCLEO_L432KC
 - NUCLEO_L476RG

Author: svastm

hal/targets.json

@@ -977,7 +977,7 @@
         "inherits": ["Target"],
         "progen": {"target": "nucleo-l432kc"},
         "detect_code": ["0770"],
-        "device_has": ["ANALOGIN", "ANALOGOUT", "I2C", "I2CSLAVE", "INTERRUPTIN", "PORTIN", "PORTINOUT", "PORTOUT", "PWMOUT", "RTC", "SERIAL", "SERIAL_FC", "SLEEP", "SPI", "SPISLAVE", "CAN", "STDIO_MESSAGES"],
+        "device_has": ["ANALOGIN", "ANALOGOUT", "I2C", "I2CSLAVE", "INTERRUPTIN", "LOWPOWERTIMER", "PORTIN", "PORTINOUT", "PORTOUT", "PWMOUT", "RTC", "SERIAL", "SERIAL_FC", "SLEEP", "SPI", "SPISLAVE", "CAN", "STDIO_MESSAGES"],
         "release_versions": ["2", "5"]
     },
     "NUCLEO_L476RG": {
@@ -989,7 +989,7 @@
         "inherits": ["Target"],
         "progen": {"target": "nucleo-l476rg"},
         "detect_code": ["0765"],
-        "device_has": ["ANALOGIN", "ANALOGOUT", "CAN", "I2C", "I2CSLAVE", "INTERRUPTIN", "PORTIN", "PORTINOUT", "PORTOUT", "PWMOUT", "RTC", "SERIAL", "SERIAL_ASYNCH", "SERIAL_FC", "SLEEP", "SPI", "SPISLAVE", "STDIO_MESSAGES"],
+        "device_has": ["ANALOGIN", "ANALOGOUT", "CAN", "I2C", "I2CSLAVE", "INTERRUPTIN", "LOWPOWERTIMER", "PORTIN", "PORTINOUT", "PORTOUT", "PWMOUT", "RTC", "SERIAL", "SERIAL_ASYNCH", "SERIAL_FC", "SLEEP", "SPI", "SPISLAVE", "STDIO_MESSAGES"],
         "release_versions": ["2", "5"]
     },
     "STM32F3XX": {
@@ -1131,7 +1131,7 @@
         "supported_toolchains": ["ARM", "uARM", "IAR", "GCC_ARM"],
         "progen": {"target": "disco-l476vg"},
         "detect_code": ["0820"],
-        "device_has": ["ANALOGIN", "ANALOGOUT", "CAN", "I2C", "I2CSLAVE", "INTERRUPTIN", "PORTIN", "PORTINOUT", "PORTOUT", "PWMOUT", "RTC", "SERIAL", "SERIAL_FC", "SLEEP", "SPI", "SPISLAVE", "STDIO_MESSAGES"],
+        "device_has": ["ANALOGIN", "ANALOGOUT", "CAN", "I2C", "I2CSLAVE", "INTERRUPTIN", "LOWPOWERTIMER", "PORTIN", "PORTINOUT", "PORTOUT", "PWMOUT", "RTC", "SERIAL", "SERIAL_FC", "SLEEP", "SPI", "SPISLAVE", "STDIO_MESSAGES"],
         "release_versions": ["2", "5"]
     },
     "MTS_MDOT_F405RG": {