[PATCH 1/2] binman: Mention split-elf in the main docs

[Simon Glass]

Since we are talking about ATF, add mention of this new feature too.

Signed-off-by: Simon Glass <sjg at chromium.org>
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 tools/binman/binman.rst | 4 ++++
 1 file changed, 4 insertions(+)

Applied to u-boot-dm, thanks!