Fix missing compilation guard around psa_crypto_driver_wrappers.c

Fix #4411.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/library/psa_crypto_driver_wrappers.c b/library/psa_crypto_driver_wrappers.c
index aab66ab..f61e5eb 100644
--- a/library/psa_crypto_driver_wrappers.c
+++ b/library/psa_crypto_driver_wrappers.c
@@ -28,6 +28,8 @@
 
 #include "mbedtls/platform.h"
 
+#if defined(MBEDTLS_PSA_CRYPTO_C)
+
 #if defined(MBEDTLS_PSA_CRYPTO_DRIVERS)
 
 /* Include test driver definition when running tests */
@@ -1777,4 +1779,5 @@
             return( PSA_ERROR_INVALID_ARGUMENT );
     }
 }
-/* End of automatically generated file. */
+
+#endif /* MBEDTLS_PSA_CRYPTO_C */