ffc: use sizeof(*pointer) instead of sizeof(struct) in memset(3) call.

Reviewed-by: NRichard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/11101)

crypto/ffc/ffc_params.c

@@ -15,7 +15,7 @@
 
 void ffc_params_init(FFC_PARAMS *params)
 {
-    memset(params, 0, sizeof(FFC_PARAMS));
+    memset(params, 0, sizeof(*params));
     params->pcounter = -1;
     params->gindex = FFC_UNVERIFIABLE_GINDEX;
 }