ARM: Handle armv7s arch defines.

Thanks to Joey Liaw.

src/lj_arch.h

@@ -169,7 +169,7 @@
 #define LJ_TARGET_UNIFYROT	2	/* Want only IR_BROR. */
 #define LJ_ARCH_NUMMODE		LJ_NUMMODE_DUAL
 
-#if __ARM_ARCH_7__ || __ARM_ARCH_7A__ || __ARM_ARCH_7R__
+#if __ARM_ARCH_7__ || __ARM_ARCH_7A__ || __ARM_ARCH_7R__ || __ARM_ARCH_7S__
 #define LJ_ARCH_VERSION		70
 #elif __ARM_ARCH_6T2__
 #define LJ_ARCH_VERSION		61