Check string equality for submodule cache check. (#7865)

Ooooops... (this check was always failing)
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8c702a4..50ac870 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -340,7 +340,7 @@
     RESULT_VARIABLE SHORT_HASH_RESULT
     OUTPUT_VARIABLE SHORT_HASH)
   string(REGEX REPLACE "\n$" "" SHORT_HASH "${SHORT_HASH}")
-  if(SHORT_HASH_RESULT EQUAL "0" AND NOT "${IREE_GIT_SHORT_HASH}" EQUAL "${SHORT_HASH}")
+  if(SHORT_HASH_RESULT EQUAL "0" AND NOT "${IREE_GIT_SHORT_HASH}" STREQUAL "${SHORT_HASH}")
     execute_process(
       COMMAND ${Python3_EXECUTABLE} scripts/git/check_submodule_init.py
       WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}