test/dm/core.c: Make pre-reloc test use pre-reloc struct

LLVM 3.5 noted:
test/dm/core.c:41:35: warning: unused variable 'test_pdata_pre_reloc' [-Wunused-const-variable]
static const struct dm_test_pdata test_pdata_pre_reloc = {

And the correct fix here is that the driver_info_pre_reloc test should
use the test_pdata_pre_reloc not test_pdata_manual variable

Cc: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

test/dm/core.c

@@ -64,7 +64,7 @@ static struct driver_info driver_info_manual = {
 
 static struct driver_info driver_info_pre_reloc = {
 	.name = "test_pre_reloc_drv",
-	.platdata = &test_pdata_manual,
+	.platdata = &test_pdata_pre_reloc,
 };
 
 void dm_leak_check_start(struct unit_test_state *uts)