psa: Remove MBEDTLS_PSA_CRYPTO_DRIVERS configuration option

The support for the PSA crypto driver interface
is not optional anymore as the implementation of
the PSA cryptography interface has been restructured
around the PSA crypto driver interface (see
psa-crypto-implementation-structure.md). There is
thus no purpose for the configuration options
MBEDTLS_PSA_CRYPTO_DRIVERS anymore.

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/tests/src/drivers/test_driver_cipher.c b/tests/src/drivers/test_driver_cipher.c
index f0cb6b2..42e79c4 100644
--- a/tests/src/drivers/test_driver_cipher.c
+++ b/tests/src/drivers/test_driver_cipher.c
@@ -20,7 +20,7 @@
 
 #include <test/helpers.h>
 
-#if defined(MBEDTLS_PSA_CRYPTO_DRIVERS) && defined(PSA_CRYPTO_DRIVER_TEST)
+#if defined(PSA_CRYPTO_DRIVER_TEST)
 #include "psa/crypto.h"
 #include "psa_crypto_cipher.h"
 #include "psa_crypto_core.h"
@@ -433,4 +433,4 @@
     (void) output_length;
     return PSA_ERROR_NOT_SUPPORTED;
 }
-#endif /* MBEDTLS_PSA_CRYPTO_DRIVERS && PSA_CRYPTO_DRIVER_TEST */
+#endif /* PSA_CRYPTO_DRIVER_TEST */