Keystore 2.0 SPI: Update the chunked streamer.

This patch makes the chunked streamer observe the simplified
Keystore 2.0 operation interface. Keystore is now required to consume
all supplied data or reject data outright if too much (more than 32KiB)
is supplied in a single transaction. This allows for a simplified
streamer logic and a simplified interface. We also no longer send
entropy to Keystore. This will be handled by the Keystore 2.0 daemon.

Test: None
Bug: 159476414
Change-Id: Ie75d10fd5d5ac0da60e23e35467d0a7873230dea