atk: Update LICENSE field version to GPLv2

* Update LICENSE field version from generic LGPL to GPLv2+ and
  LGPLv2+ to reflect the real license version.
* This change was based on setting in oe-core as well as code
  inspection.

Signed-off-by: Chase Maupin <Chase.Maupin@ti.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>

recipes/atk/atk_1.30.0.bb

@@ -1,9 +1,9 @@
 DESCRIPTION = "An accessibility toolkit for GNOME."
 SECTION = "x11/libs"
 PRIORITY = "optional"
-LICENSE = "LGPL"
+LICENSE = "GPLv2+ LGPLv2+"
 
-PR = "r1"
+PR = "r2"
 
 inherit gnome