Upcoming AMD SoCs use recovery A/B layout. Update amdfwread tool to handle it. Also add a generic read_header function to read different header types. BUG=None TEST=Run amdfwread tool against both Skyrim and Guybrush BIOS images to dump the Softfuse entry. Signed-off-by: Karthikeyan Ramasubramanian <kramasub@google.com> Change-Id: I6576eaebc611ab338885aed2ee087bf85da3ca15 Reviewed-on: https://review.coreboot.org/c/coreboot/+/66554 Reviewed-by: Raul Rangel <rrangel@chromium.org> Tested-by: build bot (Jenkins) <no-reply@coreboot.org>