Remove PSA_KEY_TYPE_IS_RAW_BYTES from crypto.h

It isn't used to define other macros and it doesn't seem that useful
for users. Remove it, we can reintroduce it if needed.

Define a similar function key_type_is_raw_bytes in the implementation
with a clear semantics: it's a key that's represented as a struct
raw_data.
diff --git a/tests/suites/test_suite_psa_crypto.function b/tests/suites/test_suite_psa_crypto.function
index 9af19fa..2d279fc 100644
--- a/tests/suites/test_suite_psa_crypto.function
+++ b/tests/suites/test_suite_psa_crypto.function
@@ -27,6 +27,13 @@
     return( 1 );
 }
 
+static int key_type_is_raw_bytes( psa_key_type_t type )
+{
+    psa_key_type_t category = type & PSA_KEY_TYPE_CATEGORY_MASK;
+    return( category == PSA_KEY_TYPE_RAW_DATA ||
+            category == PSA_KEY_TYPE_CATEGORY_SYMMETRIC );
+}
+
 static int exercise_mac_key( psa_key_slot_t key,
                              psa_key_usage_t usage,
                              psa_algorithm_t alg )
@@ -1967,7 +1974,7 @@
                                  &exported_length ) == expected_export_status );
     if( expected_export_status == PSA_SUCCESS )
     {
-        if( PSA_KEY_TYPE_IS_RAW_BYTES( type ) )
+        if( key_type_is_raw_bytes( type ) )
             TEST_ASSERT( exported_length == ( bits + 7 ) / 8 );
 #if defined(MBEDTLS_DES_C)
         if( type == PSA_KEY_TYPE_DES )