arch: arm: move cache management sources to cortex_m directory

Current implementation of cache management APIs for ARM only applies to
Cortex-M, so move it to its own directory.

Signed-off-by: Manuel Argüelles <manuel.arguelles@nxp.com>
diff --git a/arch/arm/core/aarch32/CMakeLists.txt b/arch/arm/core/aarch32/CMakeLists.txt
index 2a24639..00bc769 100644
--- a/arch/arm/core/aarch32/CMakeLists.txt
+++ b/arch/arm/core/aarch32/CMakeLists.txt
@@ -22,8 +22,6 @@
 zephyr_library_sources_ifdef(CONFIG_USERSPACE userspace.S)
 zephyr_library_sources_ifdef(CONFIG_ARM_ZIMAGE_HEADER header.S)
 
-zephyr_library_sources_ifdef(CONFIG_ARCH_CACHE cache.c)
-
 add_subdirectory_ifdef(CONFIG_CPU_CORTEX_M cortex_m)
 add_subdirectory_ifdef(CONFIG_CPU_CORTEX_M_HAS_CMSE cortex_m/cmse)
 add_subdirectory_ifdef(CONFIG_ARM_SECURE_FIRMWARE cortex_m/tz)
diff --git a/arch/arm/core/aarch32/cortex_m/CMakeLists.txt b/arch/arm/core/aarch32/cortex_m/CMakeLists.txt
index 64ac230..8d12299 100644
--- a/arch/arm/core/aarch32/cortex_m/CMakeLists.txt
+++ b/arch/arm/core/aarch32/cortex_m/CMakeLists.txt
@@ -19,6 +19,7 @@
 zephyr_library_sources_ifdef(CONFIG_THREAD_LOCAL_STORAGE __aeabi_read_tp.S)
 zephyr_library_sources_ifdef(CONFIG_SEMIHOST semihost.c)
 zephyr_library_sources_ifdef(CONFIG_PM_S2RAM pm_s2ram.c pm_s2ram.S)
+zephyr_library_sources_ifdef(CONFIG_ARCH_CACHE cache.c)
 
 if(CONFIG_NULL_POINTER_EXCEPTION_DETECTION_DWT)
   zephyr_library_sources(debug.c)
diff --git a/arch/arm/core/aarch32/cache.c b/arch/arm/core/aarch32/cortex_m/cache.c
similarity index 100%
rename from arch/arm/core/aarch32/cache.c
rename to arch/arm/core/aarch32/cortex_m/cache.c