cmd: acpi: fix listing DSDT and FACS

If field X_FIRMWARE_CTRL is filled, field FIRMWARE must be ignored. If
field X_DSDT is filled, field DSDT must be ignored.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Rebased on -next to use nomap:
Signed-off-by: Simon Glass <sjg@chromium.org>