Fix building linux-armv4 with --strict-warnings

Reviewed-by: NRich Salz <rsalz@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/6026)

crypto/arm_arch.h

@@ -69,7 +69,7 @@
 #  endif
 # endif
 
-# if !__ASSEMBLER__
+# ifndef __ASSEMBLER__
 extern unsigned int OPENSSL_armcap_P;
 # endif