The UEFI specification requires at least 128 KiB stack space. Consider this
value as a prerequisite for CONFIG_EFI_LOADER.
Mention the requirement in the CONFIG_STACK_SPACE description and decribe
that the UEFI sub-system uses CONFIG_STACK_SPACE when defining the memory
map.
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>