Set stxp70v4 build type to Release as default.

toolchain-stxp70v4.cmake

@@ -21,3 +21,6 @@ SET(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
 # for libraries and headers in the target directories
 SET(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY NEVER)
 SET(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE NEVER)
+
+set(CMAKE_BUILD_TYPE Release)
+