设备icon适配，保证图片按比例显示

文档：https://docs.qq.com/doc/DRWVqbnNJcHdJVHdB

问题- 3 :

Change-Id: I8d07593fe85427cf35d1e389772492355ce59bb3

Author: ccharlesren

Source/LinkApp/Classes/Module/DistributionNetwork/View/TIoTProductCell.m

@@ -30,6 +30,7 @@ - (void)setupUI{
 
     self.imgView = [[UIImageView alloc] init];
     self.imgView.image = [UIImage imageNamed:@"new_add_product_placeholder"];
+    self.imgView.contentMode = UIViewContentModeScaleAspectFit;
     [self addSubview:_imgView];
     [_imgView mas_makeConstraints:^(MASConstraintMaker *make) {
         make.height.mas_equalTo(68 * kScreenAllWidthScale);