driver: Remove the last trace of rcs_keygen

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
examples: Fix a syntax error

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
driver: Implement batch_size_generator

Use a size generator instead of having a fixed batch size.

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>