ucm: add If condition block

ucm: add If condition block

The syntax is simple:

If./any-if-identificator/ {
  Condition {
    Type /type_here/
    /optional defines/
  }
  True {
    /block used when condition is evaluated as true/
  }
  False {
    /block used when condition is evaluated as false/
  }
}

The Type "ControlExists" is implemented:

Condition {
  Type ControlExists
  Device "hw:${CardId}"
  Control "iface=CARD,name='Headphone Jack'"
}

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