media: atomisp: print a warning if error while setting downscaler

As warned by gcc:

    drivers/staging/media/atomisp//pci/isp/kernels/dvs/dvs_1.0/ia_css_dvs.host.c:237:31: warning: variable ‘isp_data_ptr’ set but not used [-Wunused-but-set-variable]

ia_css_vf_configure() logic has an error var that detects troubles
when setting the kernel for downscaling. The driver just ignores
it, without producing any warning. Add at least a warning message
on such cases.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/staging/media/atomisp/pci/isp/kernels/vf/vf_1.0/ia_css_vf.host.c

@@ -13,6 +13,8 @@
  * more details.
  */
 
+#include "atomisp_internal.h"
+
 #include "ia_css_vf.host.h"
 #include <assert_support.h>
 #include <ia_css_err.h>
@@ -129,6 +131,9 @@ ia_css_vf_configure(
 	const struct ia_css_binary_info *info = &binary->info->sp;
 
 	err = configure_kernel(info, out_info, vf_info, downscale_log2, &config);
+	if (err)
+		dev_warn(atomisp_dev, "Couldn't setup downscale\n");
+
 	configure_dma(&config, vf_info);
 
 	if (vf_info)