audio-caf: legacy: Sync FM flag with ALSA

 * Use QCOM_FM_ENABLED instead of BOARD_HAVE_QCOM_FM.
 * Also, guess what's the only platform using the msm7x30 audio HAL.

Change-Id: If5226d029ffa6ac88e27cb7ed2b1cf000c597f3f
Merge "audio-caf: legacy: Sync FM flag with ALSA" into cm-11.0