QCamera2: Don't initialize preview channel in ready state

 Flash torch configuration shouldn't trigger
 preview channel initialization/release once
 we are in preview ready state. At this point
 the client has already called 'startPreview'
 and the flash configuration will get applied
 once a valid preview window starts preview.

Change-Id: Ib44af3af593daabc7f1b901cd0b74eee773d20ad
Merge "QCamera2: Don't initialize preview channel in ready state"
Merge "Merge "QCamera2: Don't initialize preview channel in ready state""
Merge fd8ed288d9046d1b56611e554835dfcab83d7eca on remote branch

Change-Id: Ibd221eaf5f32dc12d7b42aa43ec6067262512e24
Merge "Merge fd8ed288d9046d1b56611e554835dfcab83d7eca on remote branch"