QCamera2: fix bug for noDisplay mode stream buf allocation
QCamera2: fix bug for noDisplay mode stream buf allocation

NoDisplay mode preview stream buffers should be allocated from
ION heap instead of from Gralloc.

Change-Id: I7bfa7bc13a025b53936ef91cdf00e18e0b223eed

maruos/android_device_lge_hammerhead,maruos/android_device_lge_hammerhead,maruos/android_device_lge_hammerhead,maruos/android_device_lge_hammerhead