Adding assembly compiler to toolchain files

Change-Id: I4530ab1aa336ae4fc487745279f74ae4ebebe3d1
diff --git a/cmake/toolchain/armclang.cmake b/cmake/toolchain/armclang.cmake
index 3fdc3a8..25c510c 100644
--- a/cmake/toolchain/armclang.cmake
+++ b/cmake/toolchain/armclang.cmake
@@ -21,6 +21,7 @@
 set(CMAKE_SYSTEM_NAME Generic)
 set(CMAKE_C_COMPILER "armclang")
 set(CMAKE_CXX_COMPILER "armclang")
+set(CMAKE_ASM_COMPILER "armclang")
 set(CMAKE_LINKER "armlink")
 
 # Convert TARGET_CPU=Cortex-M33+nofp+nodsp into