This fixes the following compile problem:
```
arv7506pw11.c: In function 'show_boot_progress':
arv7506pw11.c:59:24: error: 'return' with a value, in function returning void [-Wreturn-mismatch]
59 | return 0;
| ^
arv7506pw11.c:56:6: note: declared here
56 | void show_boot_progress(int arg)
| ^~~~~~~~~~~~~~~~~~
arv7506pw11.c:71:16: error: 'return' with a value, in function returning void [-Wreturn-mismatch]
71 | return 0;
| ^
arv7506pw11.c:56:6: note: declared here
56 | void show_boot_progress(int arg)
| ^~~~~~~~~~~~~~~~~~
```
Link: https://github.com/openwrt/openwrt/pull/18688
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
e8cfa339fe