ucm: implement MacroDefine and Macro subtree evaluation

ucm: implement MacroDefine and Macro subtree evaluation

The arguments are set as temporary variables as /MACRO_NAME/_/ARGUMENT_NAME/.

Example:

  # define new macro MyMacro with arguments ctl_name and ctl_value
  DefineMacro.MyMacro {
    BootSequence [
      cset "name='${var:MyMacro_ctl_name}' ${var:MyMacro_ctl_value}"
    ]
  }

  # instantiate macro for Speaker control (short version)
  Macro.headphone.MyMacro "ctl_name='Speaker Switch',ctl_value=off"

  # instantiate macro for Mic control (second version)
  Macro.mic.MyMacro {
	ctl_name "Mic Switch"
	ctl_value "off"
  }

Signed-off-by: Jaroslav Kysela <perex@perex.cz>