misc: poky/LICENSE has changed.. reference a hopefully more stable file

Only reference the COPYING.MIT as it is unlikely to change in
the next upgrade.
diff --git a/recipes-osmocom/tasks/task-osmocom.bb b/recipes-osmocom/tasks/task-osmocom.bb
index eb6216d..1cec91f 100644
--- a/recipes-osmocom/tasks/task-osmocom.bb
+++ b/recipes-osmocom/tasks/task-osmocom.bb
@@ -1,7 +1,6 @@
 DESCRIPTION = "Task for Osmocom tools and header files"
 LICENSE = "MIT"
-LIC_FILES_CHKSUM = "file://${COREBASE}/LICENSE;md5=3f40d7994397109285ec7b81fdeb3b58 \
-                    file://${COREBASE}/meta/COPYING.MIT;md5=3da9cfbcb788c80a0384361b4de20420"
+LIC_FILES_CHKSUM = "file://${COREBASE}/meta/COPYING.MIT;md5=3da9cfbcb788c80a0384361b4de20420"
 DEPENDS = "virtual/kernel"
 ALLOW_EMPTY_${PN} = "1"
 PR = "r2"