camera.device@3.2: Minor updates

- All usage fields should be bitfields, as should dataspace.
- Remove Stream::maxBuffers. It was accidentally duplicated in the inbound
  stream configuration; it's only meant to be set by the HAL in the
  output HalStream structures.
- Clarify overrideFormat and usage field documentation.

Test: Compiles
Bug: 32991603
Change-Id: Iac922b439fafc6726ebb6cea5bc0b3dd8921bfa8