src: remove unnecessary static qualifier in crypto_dh.cc

ZeroPadDiffieHellmanSecret() is in an anonymous namespace, so it has
static linkage already.

Signed-off-by: Darshan Sen <raisinten@gmail.com>

PR-URL: nodejs#42492
Refs: nodejs#39941
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Anna Henningsen <anna@addaleax.net>

src/crypto/crypto_dh.cc

@@ -37,9 +37,9 @@ using v8::Value;
 
 namespace crypto {
 namespace {
-static void ZeroPadDiffieHellmanSecret(size_t remainder_size,
-                                       char* data,
-                                       size_t length) {
+void ZeroPadDiffieHellmanSecret(size_t remainder_size,
+                                char* data,
+                                size_t length) {
   // DH_size returns number of bytes in a prime number.
   // DH_compute_key returns number of bytes in a remainder of exponent, which
   // may have less bytes than a prime number. Therefore add 0-padding to the