DSP: Add IAR tool chain (#1367)

Signed-off-by: TTornblom <thomas.tornblom@iar.com>
diff --git a/CMSIS/DSP/Toolchain/Tools.cmake b/CMSIS/DSP/Toolchain/Tools.cmake
index a4efcb6..6dabb64 100644
--- a/CMSIS/DSP/Toolchain/Tools.cmake
+++ b/CMSIS/DSP/Toolchain/Tools.cmake
@@ -12,7 +12,11 @@
     include(Toolchain/GCC)
 endif()
 
+if (ICCARM)
+    include(Toolchain/ICCARM)
+endif()
+
 if ((MSVC) OR (HOST))
     function(compilerSpecificCompileOptions PROJECTNAME ROOT)
     endfunction()
-endif()
\ No newline at end of file
+endif()