ramips: Fix cmpilation

ramips: Fix cmpilation

Fixes this compile problem:
```
drivers/net/ethernet/ralink/esw_rt3050.c: In function 'rt3050_esw_init':
drivers/net/ethernet/ralink/esw_rt3050.c:1467:12: error: 'pdev' is used uninitialized [-Werror=uninitialized]
 1467 |         if (!pdev)
      |            ^
drivers/net/ethernet/ralink/esw_rt3050.c:1461:33: note: 'pdev' was declared here
 1461 |         struct platform_device *pdev;
      |                                 ^~~~
cc1: all warnings being treated as errors
```

Fixes: 4ffd5aa239c1 ("treewide: fix coccinelle checks")
Signed-off-by: Hauke Mehrtens <[email protected]>