Switch poly1305-armv4.pl to named constants.

See https://rt.openssl.org/Ticket/Display.html?id=4341.

Change-Id: Ied39744dcf557e4267c7a84d6f95d78a691084e1
Reviewed-on: https://boringssl-review.googlesource.com/7225
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/crypto/poly1305/asm/poly1305-armv4.pl b/crypto/poly1305/asm/poly1305-armv4.pl
index 65b79cf..86a6070 100755
--- a/crypto/poly1305/asm/poly1305-armv4.pl
+++ b/crypto/poly1305/asm/poly1305-armv4.pl
@@ -108,7 +108,7 @@
 	and	r5,r5,r3
 
 #if	__ARM_MAX_ARCH__>=7
-	tst	r12,#1			@ check for NEON
+	tst	r12,#ARMV7_NEON		@ check for NEON
 # ifdef	__APPLE__
 	adr	r9,poly1305_blocks_neon
 	adr	r11,poly1305_blocks