compiler/blob: Constify the reader

Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

src/compiler/glsl/tests/blob_test.c

@@ -83,7 +83,7 @@ expect_equal_str(const char *expected, const char *actual, const char *test)
 }
 
 static void
-expect_equal_bytes(uint8_t *expected, uint8_t *actual,
+expect_equal_bytes(uint8_t *expected, const uint8_t *actual,
                    size_t num_bytes, const char *test)
 {
    size_t i;