[rdkb][common][app][Add mt76-vendor for hal]

[Description]
Add mt76-vendor for nl80211 vendor command for hal.
The tool may be deprecated in future, so it is a temporary workaround for vendor command.

[Release-log]
N/A

diff --git a/recipes-devtools/mt76-vendor/files/COPYING b/recipes-devtools/mt76-vendor/files/COPYING
new file mode 100644
index 0000000..7975bdb
--- /dev/null
+++ b/recipes-devtools/mt76-vendor/files/COPYING
@@ -0,0 +1 @@
+Copyright (c) Mediatek 2020