arch: arm: remove compat headers

These compat headers have been moved since at least v2.4.0 release so we
can now remove them.

Signed-off-by: Kumar Gala <[email protected]>

Author: galak

arch/arm/include/aarch32/cortex_r/exc.h

@@ -28,8 +28,8 @@
 #include <aarch32/cortex_m/stack.h>
 #include <aarch32/cortex_m/exc.h>
 #elif defined(CONFIG_CPU_CORTEX_R)
-#include <aarch32/cortex_r/stack.h>
-#include <aarch32/cortex_r/exc.h>
+#include <aarch32/cortex_a_r/stack.h>
+#include <aarch32/cortex_a_r/exc.h>
 #elif defined(CONFIG_CPU_CORTEX_A)
 #include <aarch64/exc.h>
 #endif