.gitignore: Ease /binaries pattern

The current /binaries/* hid the directory, but completely removed
it by "git-clean -d", which should not be intended.

Reported-by: Markus Heidelberg <markus.heidelberg@web.de>
Signed-off-by: Michael Roth <mroth@nessie.de>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

.gitignore

@@ -1,7 +1,7 @@
 /build_*
 /project_*
 /toolchain_*
-/binaries/*
+/binaries
 /dl
 /.auto.deps
 /.config.cmd