- Extend ub_dev_read() and ub_dev_recv() so they return the length actually
read, which allows for better control and error handling (this introduces
additional error code API_ESYSC returned by the glue mid-layer).

- Clean up definitions naming and usage.

- Other minor cosmetics.

Note these changes do not touch the API proper, so the interface between
U-Boot and standalone applications remains unchanged.

Signed-off-by: Rafal Jaworowski <raj@semihalf.com>

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

Signed-off-by: Stefan Roese <sr@denx.de>

Signed-off-by: Rafal Czubak <rcz@semihalf.com>
Acked-by: Rafal Jaworowski <raj@semihalf.com>

Signed-off-by: Rafal Jaworowski <raj@semihalf.com>

This is an API for external (standalone) applications running on top of
U-Boot, and is meant to be more extensible and robust than the existing
jumptable mechanism. It is similar to UNIX syscall approach. See api/README
for more details.

Included is the demo application using this new framework (api_examples).

Please note this is still an experimental feature, and is turned off by
default.

Signed-off-by: Rafal Jaworowski <raj@semihalf.com>