There's a merged pull request on the void-packages repository

broadcom-wl-dkms: patch for kernel 5.10
https://github.com/void-linux/void-packages/pull/28275

Description:
linux-5.10 kernel broke `broadcom-wl-dkms`, added [this patch](https://gist.github.com/joanbm/5c640ac074d27fd1d82c74a5b67a1290) to make it work.

Also removed the `linux-5.9.patch` as it is now redundant (included in the 5.10 patch) and also creates a conflict since the patches are executed alphabetically (i.e. 5.9 is applied after 5.10).