[U-Boot] [PATCH 03/53] binman: Move GetFdtSet() into blob_dtb

[sjg at google.com]

At present we check the filename to see if an entry holds a device-tree
file. It is easier to use the base class designed for this purpose.

Move this method implementation into Entry_blob_dtb and update the default
one to return an empty set.

Signed-off-by: Simon Glass <sjg at chromium.org>
---

 tools/binman/entry.py          | 5 -----
 tools/binman/etype/blob_dtb.py | 9 +++++++++
 2 files changed, 9 insertions(+), 5 deletions(-)

Applied to u-boot-dm, thanks!