Execute a single command from a macro register.
Macro register to read. Value 0 means the FT800 will fetch the command from REG_MACRO_0 to execute.
Value 1 means the FT800 will fetch the command from REG_MACRO_1 to execute.
The content of REG_MACRO_0 or REG_MACRO_1 shall be a valid display list command, otherwise the behavior