Require ARMv5 for arm. All current kernels are for ARMv5 or later, and it

will allow us to clean out old ARMv4 (and earlier) specific assembly.

Relnotes:	yes

sys/arm/arm/machdep.c

@@ -77,6 +77,7 @@ __FBSDID("$FreeBSD$");
 #include <vm/vm_page.h>
 #include <vm/vm_pager.h>
 
+#include <machine/asm.h>
 #include <machine/debug_monitor.h>
 #include <machine/machdep.h>
 #include <machine/metadata.h>
@@ -109,6 +110,10 @@ __FBSDID("$FreeBSD$");
 #error armv6 requires INTRNG
 #endif
 
+#ifndef _ARM_ARCH_5E
+#error FreeBSD requires ARMv5 or later
+#endif
+
 struct pcpu __pcpu[MAXCPU];
 struct pcpu *pcpup = &__pcpu[0];