frameworks/av: Add support for FM feature

Add FM handle key and volume key to AudioParamater
class which is used to initimate Audio HAL to
that FM device is connected and apply correct
volume to FM stream

Change-Id: If5fa14faf7946ab27eb42b89546dc2274b24f754
(cherry picked from commit 165f20759433d0137a292b457aa783f801f13277)
(cherry picked from commit c98b484de0877e159f00b3b01d622b6539f0b2bc)
(cherry picked from commit f752d489bb85a94b81d38c72333409b4384d860a)