Add a bunch more missing ENDs to assembler routines.

This isn't everything; I've missed out those x86 files that are

Change-Id: Idb7bb1a68796d6c0b70ea2b5c3300e49da6c62d2
diff --git a/libc/arch-x86/string/swab.S b/libc/arch-x86/string/swab.S
index 3055860..2f6cfb2 100644
--- a/libc/arch-x86/string/swab.S
+++ b/libc/arch-x86/string/swab.S
@@ -65,3 +65,4 @@
 L4:	popl	%edi
 	popl	%esi
 	ret
+END(swab)