vbe_simple_read_bootflow() calls vbe_simple_read_bootflow_fw()
which is only available when BOOTMETH_VBE_SIMPLE_FW is on.
Signed-off-by: Bin Meng <bmeng@tinylab.org>
Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Simon Glass <sjg@chromium.org>