aes/asm/bsaes-armv7: fix kernel-side XTS and harmonize with Linux.

XTS bug spotted and fix suggested by Adrian Kotelba.
Reviewed-by: NTim Hudson <tjh@openssl.org>

crypto/aes/asm/bsaes-armv7.pl

@@ -702,7 +702,7 @@ $code.=<<___;
 # define BSAES_ASM_EXTENDED_KEY
 # define XTS_CHAIN_TWEAK
 # define __ARM_ARCH__ __LINUX_ARM_ARCH__
-# define __ARM_MAX_ARCH__ __LINUX_ARM_ARCH__
+# define __ARM_MAX_ARCH__ 7
 #endif
 
 #ifdef __thumb__
@@ -2078,9 +2078,11 @@ bsaes_xts_decrypt:
 	vld1.8	{@XMM[8]}, [r0]			@ initial tweak
 	adr	$magic, .Lxts_magic
 
+#ifndef	XTS_CHAIN_TWEAK
 	tst	$len, #0xf			@ if not multiple of 16
 	it	ne				@ Thumb2 thing, sanity check in ARM
 	subne	$len, #0x10			@ subtract another 16 bytes
+#endif
 	subs	$len, #0x80
 
 	blo	.Lxts_dec_short