psa: Add PSA_DRIVER_GET_ENTROPY_BLOCK in temporary place

For PSA crypto drivers, pull request Mbed-TLS#5464 will add
PSA_DRIVER_GET_ENTROPY_BLOCK in a header in include/psa. To be
able to build and test, it's temporarily added in the internal
header file for PSA driver wrapper.

Signed-off-by: François Beerten <francois.beerten@silexinsight.com>
Signed-off-by: Francois Beerten <fbeerten.git@b10eng.com>

library/psa_crypto_driver_wrappers.h

@@ -373,6 +373,8 @@ struct psa_entropy_acc {
 #endif
 };
 
+#define PSA_DRIVER_GET_ENTROPY_BLOCK  1
+
 int mbedtls_accumulate_psa_entropy(struct psa_entropy_acc *acc,
     size_t estimate_bits, uint8_t *p);