Fix unused parameter warning in some configurations

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index a4ca1d0..5c560c2 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -505,6 +505,7 @@
             break;
     }
 
+    (void) bits_is_sloppy;
     return( MBEDTLS_ECP_DP_NONE );
 }
 #endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR) ||