Camera: Support 60fps during constrained HFR.

Currently we are calculating the requestList size using a fixed preview
size of 30fps. Support 60fps along with 30fps preview. This change
also updates the requestList size to 1 for high speed recording preview.

Test: CTS RecordingTest on pixel 4 device.

Bug: 200310682
Change-Id: I8c417eefd0d2584e8a4a1c45c0f023a2dc405cb2