arm64: LLVMLinux: Add missing abort() for AARCH64

Add missing abort for arch aarch64.
Signed-off-by: Mark Charlebois <charlebm@gmail.com>

arch/arm64/kernel/traps.c

@@ -340,6 +340,15 @@ void __pgd_error(const char *file, int line, unsigned long val)
 	printk("%s:%d: bad pgd %016lx.\n", file, line, val);
 }
 
+void abort(void)
+{
+	BUG();
+
+	/* if that doesn't kill us, halt */
+	panic("Oops failed to kill thread");
+}
+EXPORT_SYMBOL(abort);
+
 void __init trap_init(void)
 {
 	return;