Align setting tflu optimization level with tflu upstream.

Change-Id: I1e80d22c9cf1eb59a5bf2c6bd2f06b6a0024c911
diff --git a/tensorflow.cmake b/tensorflow.cmake
index ee9c68a..66a63d4 100644
--- a/tensorflow.cmake
+++ b/tensorflow.cmake
@@ -42,8 +42,7 @@
 set(TFLU_TARGET "cortex_generic")
 set(TFLU_TARGET_ARCH ${CMAKE_SYSTEM_PROCESSOR}${CPU_FEATURES})
 set(TFLU_BUILD_TYPE "release" CACHE STRING "Tensorflow Lite Mirco build type, can be release or debug")
-set(TFLU_DEBUG_OPTIMIZATION CACHE STRING "Tensorflow Lite Micro default optimization level for debug builds")
-set(TFLU_RELEASE_OPTIMIZATION CACHE STRING "Tensorflow Lite Micro default optimization level for debug builds")
+set(TFLU_OPTIMIZATION_LEVEL CACHE STRING "Tensorflow Lite Micro optimization level")
 
 if(CORE_SOFTWARE_ACCELERATOR STREQUAL NPU)
     set(TFLU_ETHOSU_LIBS $<TARGET_FILE:ethosu_core_driver>)
@@ -56,7 +55,7 @@
 
 # Command and target
 add_custom_target(tflu_gen ALL
-                  COMMAND make -j${J} -f ${TFLU_PATH}/tools/make/Makefile microlite TARGET=${TFLU_TARGET} TARGET_ARCH=${TFLU_TARGET_ARCH} CC_TOOL=${TFLU_CC} CXX_TOOL=${TFLU_CXX} AR_TOOL=${TFLU_AR} GENDIR=${TFLU_GENDIR} CMSIS_PATH=${CMSIS_PATH} ETHOSU_DRIVER_PATH=${CORE_DRIVER_PATH} ETHOSU_DRIVER_LIBS=${TFLU_ETHOSU_LIBS} TAGS="${TFLU_TAGS}" BUILD_TYPE=${TFLU_BUILD_TYPE}  $<$<BOOL:${TFLU_DEBUG_OPTIMIZATION}>:DEBUG_DEFAULT_OPTIMIZATION=${TFLU_DEBUG_OPTIMIZATION}> $<$<BOOL:${TFLU_RELEASE_OPTIMIZATION}>:RELEASE_DEFAULT_OPTIMIZATION=${TFLU_RELEASE_OPTIMIZATION}>
+                  COMMAND make -j${J} -f ${TFLU_PATH}/tools/make/Makefile microlite TARGET=${TFLU_TARGET} TARGET_ARCH=${TFLU_TARGET_ARCH} CC_TOOL=${TFLU_CC} CXX_TOOL=${TFLU_CXX} AR_TOOL=${TFLU_AR} GENDIR=${TFLU_GENDIR} CMSIS_PATH=${CMSIS_PATH} ETHOSU_DRIVER_PATH=${CORE_DRIVER_PATH} ETHOSU_DRIVER_LIBS=${TFLU_ETHOSU_LIBS} TAGS="${TFLU_TAGS}" BUILD_TYPE=${TFLU_BUILD_TYPE}  $<$<BOOL:${TFLU_OPTIMIZATION_LEVEL}>:OPTIMIZATION_LEVEL=${TFLU_OPTIMIZATION_LEVEL}>
                   WORKING_DIRECTORY ${TENSORFLOW_PATH})
 
 # Create library and link library to custom target