ARM assembly pack: make it work with older assembler.

Reviewed-by: NRichard Levitte <levitte@openssl.org>
Reviewed-by: NPaul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/6043)

crypto/armv4cpuid.pl

@@ -125,7 +125,7 @@ CRYPTO_memcmp:
 
 	ldmia	sp!,{r4,r5}
 .Lno_data:
-	neg	r0,ip
+	rsb	r0,ip,#0
 	mov	r0,r0,lsr#31
 #if __ARM_ARCH__>=5
 	bx	lr

crypto/ec/asm/ecp_nistz256-armv4.pl

@@ -1633,7 +1633,7 @@ ___
 $code.=<<___;
 .Ladd_done:
 	add	sp,sp,#32*18+16+16	@ +16 means "skip even over saved r0-r3"
-#if __ARM_ARCH__>=5 || defined(__thumb__)
+#if __ARM_ARCH__>=5 || !defined(__thumb__)
 	ldmia	sp!,{r4-r12,pc}
 #else
 	ldmia	sp!,{r4-r12,lr}

crypto/modes/asm/ghashv8-armx.pl

@@ -70,6 +70,7 @@ my ($t0,$t1,$t2,$xC2,$H,$Hhl,$H2)=map("q$_",(8..14));
 $code=<<___;
 #include "arm_arch.h"
 
+#if __ARM_MAX_ARCH__>=7
 .text
 ___
 $code.=".arch	armv8-a+crypto\n"	if ($flavour =~ /64/);
@@ -699,6 +700,7 @@ ___
 $code.=<<___;
 .asciz  "GHASH for ARMv8, CRYPTOGAMS by <appro\@openssl.org>"
 .align  2
+#endif
 ___
 
 if ($flavour =~ /64/) {			######## 64-bit code