Remove useless guard around include

Including a header is harmless, so we can include do it unconditionally.

The condition was wrong, should have been USE_PSA || PROTO_TLS1_3. If we
just fixed to condition, then we would need to make sure things like:

    #define MBEDTLS_TLS1_3_MD_MAX_SIZE         PSA_HASH_MAX_SIZE

are also guarded, which is useless (extra defines are harmless) and
annoying, so just remove the condition altogether.

Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 3811fd2..b40b4f4 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -52,9 +52,7 @@
 #include "mbedtls/platform_time.h"
 #endif
 
-#if defined(MBEDTLS_USE_PSA_CRYPTO)
 #include "psa/crypto.h"
-#endif /* MBEDTLS_USE_PSA_CRYPTO */
 
 /*
  * SSL Error codes