sfc: parse headers of devlink flash images

This parsing is necessary to obtain the metadata which will be
 used in a subsequent patch to write the image to the device.

Signed-off-by: Edward Cree <ecree.xilinx@gmail.com>
Link: https://patch.msgid.link/65318300f3f1b1462925f917f7c0d0ac833955ae.1739186253.git.ecree.xilinx@gmail.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>