[PATCH v4 2/2] bootstd: Replicate the dtb-filename quirks of distroboot

[Simon Glass]

For EFI, the distro boot scripts search in three different directories
for the .dtb file. The SOC-based filename fallback is supported only for
32-bit ARM.

Adjust the code to mirror this behaviour.

Also some boards can use a prior-stage FDT if one is not found in the
normal way. Support this and show a message in that case.

Signed-off-by: Simon Glass <sjg at chromium.org>
Suggested-by: Mark Kettenis <kettenis at openbsd.org>
---

Changes in v4:
- Update commit message to avoid mentioning a warning
- Rebase to -master instead of -next

Changes in v3:
- Change the message from a warning to a statement

Changes in v2:
- Allow use of the prior-stage FDT if nothing else is found
- Warn about using a prior-stage FDT

 boot/bootflow.c     |  3 ++
 boot/bootmeth_efi.c | 70 +++++++++++++++++++++++++++++++++++++++------
 include/bootflow.h  | 14 +++++++++
 3 files changed, 78 insertions(+), 9 deletions(-)

Applied to u-boot-dm/next, thanks!