Add support for Cortex-M85

Rely on CMSIS code for initializing Cortex-M85 devices.

Fallback to mcpu=cortex-m55 for gcc until support for cortex-m85 is
available.

Change-Id: I8b47563c3f0f44e35735a569f2abf8a308948e67
diff --git a/cmake/toolchain/armclang.cmake b/cmake/toolchain/armclang.cmake
index f65b9a5..aa19ff4 100644
--- a/cmake/toolchain/armclang.cmake
+++ b/cmake/toolchain/armclang.cmake
@@ -1,5 +1,5 @@
 #
-# Copyright (c) 2020-2021 Arm Limited. All rights reserved.
+# Copyright (c) 2020-2022 Arm Limited. All rights reserved.
 #
 # SPDX-License-Identifier: Apache-2.0
 #
@@ -42,7 +42,7 @@
     string(APPEND __LINK_TARGET ".no_fp")
 endif()
 
-if (CMAKE_SYSTEM_PROCESSOR STREQUAL "cortex-m55")
+if ("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "cortex-m55")
     set(__LINK_TARGET 8.1-M.Main.dsp)
 endif()