feat(synquacer): add FWU Multi Bank Update support

feat(synquacer): add FWU Multi Bank Update support

Add FWU Multi Bank Update support. This reads the platform metadata
and update the FIP base address so that BL2 can load correct BL3X
based on the boot index.

Cc: Sumit Garg <sumit.garg@linaro.org>
Cc: Masahisa Kojima <masahisa.kojima@linaro.org>
Cc: Manish V Badarkhe <manish.badarkhe@arm.com>
Cc: Leonardo Sandoval <leonardo.sandoval@linaro.org>
Change-Id: I5d96972bc4b3b9a12a8157117e53a05da5ce89f6
Signed-off-by: Masami Hiramatsu <masami.hiramatsu@linaro.org>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>