Fixed CVE-2018-8788

Thanks to Eyal Itkin from Check Point Software Technologies.
BOOL nsc_context_set_pixel_format(NSC_CONTEXT* context, UINT32 pixel_format)
{
	if (!context)
		return FALSE;

	context->format = pixel_format;
	return TRUE;
}

BOOL nsc_context_set_pixel_format(NSC_CONTEXT* context, UINT32 pixel_format)
{
	if (!context)
		return FALSE;

	context->format = pixel_format;
	return TRUE;
}
