Extract Secp256r1 from the prototype

Signed-off-by: Gabor Mezei <gabor.mezei@arm.com>
diff --git a/tests/suites/test_suite_ecp.function b/tests/suites/test_suite_ecp.function
index ee9f157..333435a 100644
--- a/tests/suites/test_suite_ecp.function
+++ b/tests/suites/test_suite_ecp.function
@@ -9,8 +9,7 @@
 #include "bignum_mod_raw_invasive.h"
 
 #if defined(MBEDTLS_TEST_HOOKS) &&                  \
-    (defined(MBEDTLS_ECP_DP_SECP256R1_ENABLED) ||  \
-    defined(MBEDTLS_ECP_DP_SECP384R1_ENABLED))
+    defined(MBEDTLS_ECP_DP_SECP384R1_ENABLED)
 #define HAVE_FIX_NEGATIVE
 #endif