arm: recognize instruction fetch pagefault

. an instruction fetch pagefault generates a prefetch
	  abort exception, this should also be a source of
	  a pagefault event
	. the saved_lr argument to the C exception handler was
	  sometimes an address, sometimes a pointer to that address;
	  the kernel sometimes dereferences it, so it should always be
	  an in-kernel address, never a userspace address. fix in mpx.S
	  makes it always a pointer.
	. move dumping of all processes over serial out of
	  the arch-specific arch_system.c

kernel/arch/i386/arch_system.c

@@ -421,17 +421,6 @@ static void ser_debug(const int c)
 }
 
 #if DEBUG_SERIAL
-void ser_dump_proc()
-{
-	struct proc *pp;
-
-	for (pp= BEG_PROC_ADDR; pp < END_PROC_ADDR; pp++)
-	{
-		if (isemptyp(pp))
-			continue;
-		print_proc_recursive(pp);
-	}
-}
 
 static void ser_dump_vfs()
 {