Revert "Use unified ARM assembly."

This reverts commit 2cd63877b5. We've
since imported a change to upstream which adds some #defines that should
do the same thing on clang. (Though if gas accepts unified assembly too,
that does seem a better approach. Ah well. Diverging on these files is
expensive.)

This is to reduce the diff and make applying some subsequent changes
easier.

Change-Id: I3f5eae2a71919b291a8de9415b894d8f0c67e3cf
Reviewed-on: https://boringssl-review.googlesource.com/17107
Reviewed-by: Adam Langley <agl@google.com>

crypto/fipsmodule/modes/asm/ghash-armv4.pl

@@ -135,8 +135,6 @@ ___
 $code=<<___;
 #include <openssl/arm_arch.h>
 
-.syntax unified
-
 .text
 .code	32
 
@@ -215,7 +213,7 @@ gcm_ghash_4bit:
 	eor	$Zlh,$Zlh,$Zhl,lsl#28
 	ldrh	$Tll,[sp,$nlo]		@ rem_4bit[rem]
 	eor	$Zhl,$Thl,$Zhl,lsr#4
-	ldrbpl	$nlo,[$inp,$cnt]
+	ldrplb	$nlo,[$inp,$cnt]
 	eor	$Zhl,$Zhl,$Zhh,lsl#28
 	eor	$Zhh,$Thh,$Zhh,lsr#4
 
@@ -225,7 +223,7 @@ gcm_ghash_4bit:
 	add	$nhi,$nhi,$nhi
 	ldmia	$Thh,{$Tll-$Thh}	@ load Htbl[nhi]
 	eor	$Zll,$Tll,$Zll,lsr#4
-	ldrbpl	$Tll,[$Xi,$cnt]
+	ldrplb	$Tll,[$Xi,$cnt]
 	eor	$Zll,$Zll,$Zlh,lsl#28
 	eor	$Zlh,$Tlh,$Zlh,lsr#4
 	ldrh	$Tlh,[sp,$nhi]
@@ -243,7 +241,7 @@ gcm_ghash_4bit:
 	add	$inp,$inp,#16
 	mov	$nhi,$Zll
 ___
-	&Zsmash("cmp\t$inp,$len","ldrbne\t$nlo,[$inp,#15]");
+	&Zsmash("cmp\t$inp,$len","ldrneb\t$nlo,[$inp,#15]");
 $code.=<<___;
 	bne	.Louter
 
@@ -301,7 +299,7 @@ gcm_gmult_4bit:
 	eor	$Zlh,$Zlh,$Zhl,lsl#28
 	ldrh	$Tll,[$rem_4bit,$nlo]	@ rem_4bit[rem]
 	eor	$Zhl,$Thl,$Zhl,lsr#4
-	ldrbpl	$nlo,[$Xi,$cnt]
+	ldrplb	$nlo,[$Xi,$cnt]
 	eor	$Zhl,$Zhl,$Zhh,lsl#28
 	eor	$Zhh,$Thh,$Zhh,lsr#4