android: boot: rename andr_img_hdr -> andr_boot_img_hdr_v0

android: boot: rename andr_img_hdr -> andr_boot_img_hdr_v0

Android introduced boot header version 3 or 4.
The header structure change with version 3 and 4 to support
the new updates such as:
- Introducing Vendor boot image: with a vendor ramdisk
- Bootconfig feature (v4)

Change andr_img_hdr struct name to maintain support for version v0,
v1 and v2 while introducing version 3 and 4.

Signed-off-by: Safae Ouajih <souajih@baylibre.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
Tested-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>