Change the fix_quasi_reduction function to static

Signed-off-by: Gabor Mezei <gabor.mezei@arm.com>
diff --git a/library/bignum_mod_raw_invasive.h b/library/bignum_mod_raw_invasive.h
index 3d4afed..7770c0a 100644
--- a/library/bignum_mod_raw_invasive.h
+++ b/library/bignum_mod_raw_invasive.h
@@ -28,6 +28,8 @@
 #include "mbedtls/bignum.h"
 #include "bignum_mod.h"
 
+#if defined(MBEDTLS_TEST_HOOKS)
+
 /** Convert an MPI to its canonical representative.
  *
  * \note Currently handles the case when `N->int_rep` is
@@ -44,4 +46,6 @@
 int mbedtls_mpi_mod_raw_fix_quasi_reduction(mbedtls_mpi_uint *X,
                                             const mbedtls_mpi_mod_modulus *N);
 
+#endif /* MBEDTLS_TEST_HOOKS */
+
 #endif /* MBEDTLS_BIGNUM_MOD_RAW_INVASIVE_H */
diff --git a/tests/suites/test_suite_bignum_mod_raw.function b/tests/suites/test_suite_bignum_mod_raw.function
index 2c4a0e6..d59cdde 100644
--- a/tests/suites/test_suite_bignum_mod_raw.function
+++ b/tests/suites/test_suite_bignum_mod_raw.function
@@ -340,7 +340,7 @@
 }
 /* END_CASE */
 
-/* BEGIN_CASE */
+/* BEGIN_CASE depends_on:MBEDTLS_TEST_HOOKS */
 void mpi_mod_raw_fix_quasi_reduction(char *input_N,
                                      char *input_A,
                                      char *result)
@@ -381,7 +381,7 @@
 }
 /* END_CASE */
 
-/* BEGIN_CASE */
+/* BEGIN_CASE depends_on:MBEDTLS_TEST_HOOKS */
 void mpi_mod_raw_fix_quasi_reduction_neg(char *input_N,
                                          char *input_A,
                                          char *result)