libusbgx: add license hashes

Signed-off-by: John Keeping <john@metanate.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/libusbgx/libusbgx.hash

@@ -1,2 +1,4 @@
 # Locally computed:
 sha256  b15abc89a0ef82c6a650cc1d58b5ba50f7ce076db392add84caabcd86c608ee2  libusbgx-libusbgx-v0.2.0.tar.gz
+sha256  8177f97513213526df2cf6184d8ff986c675afb514d4e68a404010521b880643  COPYING
+sha256  dc626520dcd53a22f727af3ee42c770e56c97a64fe3adb063799d8ab032fe551  COPYING.LGPL