.gitignore: Update to the new directory hierachy

Signed-off-by: Michael Roth <mroth@nessie.de>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

.gitignore

@@ -1,7 +1,4 @@
-/build_*
-/project_*
-/toolchain_*
-/binaries
+/output
 /dl
 /.auto.deps
 /.config.cmd