crypto: api - Fix build error when modules are disabled

The commit 59afdc7b32143528524455039e7557a46b60e4c8 ("crypto:
api - Move module sig ifdef into accessor function") broke the
build when modules are completely disabled because we directly
dereference module->name.

This patch fixes this by using the accessor function module_name.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/crypto/algapi.c b/crypto/algapi.c
index c63836f..3103e6a 100644
--- a/crypto/algapi.c
+++ b/crypto/algapi.c
@@ -46,7 +46,7 @@
 {
 	if (fips_enabled && mod && !module_sig_ok(mod))
 		panic("Module %s signature verification failed in FIPS mode\n",
-		      mod->name);
+		      module_name(mod));
 }
 
 static int crypto_check_alg(struct crypto_alg *alg)