cmake: Add support for Cortex-M23 to build system

Add Cortex-M23 specific CMake file and update CompilerArmClang67
settings file.

Change-Id: Ieaee7a00ea267fb5eb9cdb7574569a30dc35e5cf
Signed-off-by: Mate Toth-Pal <mate.toth-pal@arm.com>
diff --git a/cmake/Common/CpuM23.cmake b/cmake/Common/CpuM23.cmake
new file mode 100644
index 0000000..19e640b
--- /dev/null
+++ b/cmake/Common/CpuM23.cmake
@@ -0,0 +1,11 @@
+#-------------------------------------------------------------------------------
+# Copyright (c) 2018, Arm Limited. All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#
+#-------------------------------------------------------------------------------
+
+#This file gatrhers Cortex-M23 specific settings which control the build system.
+set(ARM_CPU_ARHITECTURE "ARM8-M-BASE")
+
+set(ARM_CPU_TYPE "Cortex-M23")