x265: dont build high bit-depths for 32bit systems

[B4dM4n]

Motivation for this change

Since #92052 the x265.i686-linux build is failing. The rewrite removed a is64bit check for the high bit depth flags, which fail to build on 32bit systems.

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.

CC @dominikh

[B4dM4n]

Result of nixpkgs-review pr 96260 1

1 package failed to build:

- airwave

8 packages built:

- driversi686Linux.libvdpau-va-gl
- javacard-devkit
- pipelight
- playonlinux
- wine (wineFull)
- wineStaging (wine-staging)
- wineWowPackages.full
- winetricks

[mat8913]

Thanks. I needed this to build wine.