Change the Kconfig from a "choice" to a conditional block, allowing
multiple FWU metadata storage drivers to be selected simultaneously
instead of being mutually exclusive.

This enables systems with FWU metadata on different storage types
(e.g., both GPT-partitioned block devices and MTD devices) to have
both drivers compiled in. The board can then select the appropriate
driver at runtime based on the devicetree description.

The change converts FWU_MDATA to a menuconfig and replaces the
"choice/endchoice" block with "if FWU_MDATA/endif", making
FWU_MDATA_GPT_BLK default to 'y' for backward compatibility.

Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
Acked-by: Sughosh Ganu <sughosh.ganu@arm.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

In the FWU Multi Bank Update feature, the information about the
updatable images is stored as part of the metadata, on a separate
region. Add a driver for reading from and writing to the metadata
when the updatable images and the metadata are stored on a raw
MTD region.
The code is divided into core under drivers/fwu-mdata/ and some helper
functions clubbed together under lib/fwu_updates/

Signed-off-by: Masami Hiramatsu <masami.hiramatsu@linaro.org>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

In the FWU Multi Bank Update feature, the information about the
updatable images is stored as part of the metadata, on a separate
partition. Add a driver for reading from and writing to the metadata
when the updatable images and the metadata are stored on a block
device which is formatted with GPT based partition scheme.

Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>