ARMv4 assembly pack: harmonize Thumb-ification of iOS build.

Three modules were left behind in
I59df0b567e8e80befe5c399f817d6410ddafc577.

(Imported from upstream's c93f06c12f10c07cea935abd78a07a037e27f155.)

This actually meant functions defined in those two files were
non-functional. I'm guessing no one noticed upstream because, if you go
strictly by iOS compile-time capabilities, all this code is unreachable
on ios32, only ios64.

Change-Id: I55035edf2aebf96d14bdf66161afa2374643d4ec
Reviewed-on: https://boringssl-review.googlesource.com/17113
Reviewed-by: David Benjamin <davidben@google.com>

crypto/fipsmodule/aes/asm/aesv8-armx.pl

@@ -63,9 +63,12 @@ $code.=<<___ if ($flavour =~ /64/);
 .arch  armv8-a+crypto
 #endif
 ___
-$code.=".arch	armv7-a\n.fpu	neon\n.code	32\n"	if ($flavour !~ /64/);
-		#^^^^^^ this is done to simplify adoption by not depending
-		#	on latest binutils.
+$code.=<<___						if ($flavour !~ /64/);
+.arch	armv7-a	// don't confuse not-so-latest binutils with argv8 :-)
+.fpu	neon
+.code	32
+#undef	__thumb2__
+___
 
 # Assembler mnemonics are an eclectic mix of 32- and 64-bit syntax,
 # NEON is mostly 32-bit mnemonics, integer - mostly 64. Goal is to

crypto/fipsmodule/modes/asm/ghashv8-armx.pl

@@ -71,7 +71,11 @@ $code.=<<___ if ($flavour =~ /64/);
 .arch  armv8-a+crypto
 #endif
 ___
-$code.=".fpu	neon\n.code	32\n"	if ($flavour !~ /64/);
+$code.=<<___				if ($flavour !~ /64/);
+.fpu	neon
+.code	32
+#undef	__thumb2__
+___
 
 ################################################################################
 # void gcm_init_v8(u128 Htable[16],const u64 H[2]);