qsr1000: Allow uboot to handle both Image Formats

Allow uboot to detect whether a given image was
created with a Quantenna or upstream mkimage and
handle it accordingly.

Quantennas mkimage pads the image header with 0s
up until an 8k boundary, and sets ARCH_ID to 19.
Upstream mkimage does no padding and sets ARCH_ID to
23.
Now we can support both.
I have also patched our mkimage (go/fibercl/78334 and
go/fibercl/78020) tofollow upstream behaviour rather
than Quantenna.

Change-Id: Ie15c234e7bcb4aac3d9bbf481582dc4f6100965f
5 files changed