This commit adds a CHOOSE_MACRO_VA_ARG() selector to allow selection between two
versions of a macro based on the number of arguments. This replaces the previous
portGET_ARGUMENT_COUNT() selector.
- portYIELD_FROM_ISR() now uses CHOOSE_MACRO_VA_ARG()
- portYIELD_FROM_ISR(arg) version added to risc-v port
- Old vPortEvaluateYieldFromISR() and portGET_ARGUMENT_COUNT removed
