cmake: change 'gsm' to 'grgsm'

Change-Id: I130a7912e179b1f04e68eb131e06800becca5a00
diff --git a/CMakeLists.txt b/CMakeLists.txt
index f73bfbe..e8d7ef0 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -176,5 +176,5 @@
 ########################################################################
 
 install(FILES cmake/Modules/gr-gsmConfig.cmake
-    DESTINATION ${CMAKE_MODULES_DIR}/gsm
+    DESTINATION ${CMAKE_MODULES_DIR}/grgsm
 )