wifi: add a new "loading" state

Set wlan.driver.status to "loading" in wifi_load_driver to allow
external action being triggered by property change.

Change-Id: Ia4363de4c4e0e1a1c4759f5699fd5ea6e1bc3182
Primary output check for sonification is removed.

- When there are 3 different tracks (Ringtone, Music and Touchtone)
   the device switch happens for touchtones to primary if the primary
   output is active. This can lead to music being played in combo
   due to timing issue.
 - This is mainly because we have a check for, primary output if
   active we return true for SONIFICATION. This will set SONIFICATION
   for touch tones and this device switch will come after music device
   is set.
 - Hence music will start playing as SONIFICATION.
 - We have removed the primar output check for getting device strategy

Change-Id: Ibe2c381a887a49ea8b776fb2148f38b61532d021
CRs-Fixed: 456842
libhardware_legacy: Increase stream mute time

- Increase the stream mute time to avoid audio glitches
  while switching between combo devices.

Change-Id: I8b47e6e8b977b1025310fd2b16b452a6c11005bd
CRs-Fixed: 448577