STM32 : update LPTICKER_DELAY_TICKS value
STM32 : update LPTICKER_DELAY_TICKS value

- decreased to 1 for low freq targets
- removed for high freq targets
- not changed for targets with LPTIM

c1728p9/mbed-os,betzw/mbed-os,betzw/mbed-os,mbedmicro/mbed,kjbracey-arm/mbed,betzw/mbed-os,mbedmicro/mbed,c1728p9/mbed-os,mbedmicro/mbed,c1728p9/mbed-os,andcor02/mbed-os,c1728p9/mbed-os,kjbracey-arm/mbed,betzw/mbed-os,betzw/mbed-os,c1728p9/mbed-os,andcor02/mbed-os,kjbracey-arm/mbed,mbedmicro/mbed,andcor02/mbed-os,c1728p9/mbed-os,andcor02/mbed-os,andcor02/mbed-os,kjbracey-arm/mbed,andcor02/mbed-os,mbedmicro/mbed,betzw/mbed-os