Removed f_rng param from mbedtls_rsa_rsassa_pss_verify

Commit removes f_rng parameter from
mbedtls_rsa_rsassa_pss_verify function in
preparation of mode parameter removal.

Signed-off-by: Thomas Daubney <thomas.daubney@arm.com>
diff --git a/library/rsa.c b/library/rsa.c
index 333747e..99a56b7 100644
--- a/library/rsa.c
+++ b/library/rsa.c
@@ -2297,7 +2297,6 @@
  * Simplified PKCS#1 v2.1 RSASSA-PSS-VERIFY function
  */
 int mbedtls_rsa_rsassa_pss_verify( mbedtls_rsa_context *ctx,
-                           int (*f_rng)(void *, unsigned char *, size_t),
                            int mode,
                            mbedtls_md_type_t md_alg,
                            unsigned int hashlen,
@@ -2317,7 +2316,7 @@
                              ? (mbedtls_md_type_t) ctx->hash_id
                              : md_alg;
 
-    return( mbedtls_rsa_rsassa_pss_verify_ext( ctx, f_rng, NULL, mode,
+    return( mbedtls_rsa_rsassa_pss_verify_ext( ctx, NULL, NULL, mode,
                                        md_alg, hashlen, hash,
                                        mgf1_hash_id, MBEDTLS_RSA_SALT_LEN_ANY,
                                        sig ) );
@@ -2424,7 +2423,7 @@
 
 #if defined(MBEDTLS_PKCS1_V21)
         case MBEDTLS_RSA_PKCS_V21:
-            return mbedtls_rsa_rsassa_pss_verify( ctx, NULL, MBEDTLS_RSA_PUBLIC, md_alg,
+            return mbedtls_rsa_rsassa_pss_verify( ctx, MBEDTLS_RSA_PUBLIC, md_alg,
                                           hashlen, hash, sig );
 #endif