board: synquacer: Update the flash image layout

The SynQuacer Developerbox, in EFI mode, supports A/B capsule
updates and single image ones. The flash layout in the latter case is
outdated, update it with the new offsets and images

Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Tested-By: Masahisa Kojima <masahisa.kojima@linaro.org>