linux_testing: disable NFS_LOCALIO on aarch64-linux

This breaks the build like this:

      /nix/store/f3k0rdhcd2cx57phx755c2xixgifw5m5-binutils-2.42/bin/ld: Unexpected GOT/PLT entries detected!
      /nix/store/f3k0rdhcd2cx57phx755c2xixgifw5m5-binutils-2.42/bin/ld: Unexpected run-time procedure linkages detected!
      /nix/store/f3k0rdhcd2cx57phx755c2xixgifw5m5-binutils-2.42/bin/ld: fs/nfs/localio.o: in function `nfs_local_iocb_alloc':
      /build/source/build/../fs/nfs/localio.c:290:(.text+0x324): undefined reference to `nfs_to'
      [...]

Reported as https://lore.kernel.org/all/[email protected]/

Author: Ma27

pkgs/os-specific/linux/kernel/common-config.nix

@@ -639,7 +639,10 @@ let
       NFS_V4_1              = yes;  # NFSv4.1 client support
       NFS_V4_2              = yes;
       NFS_V4_SECURITY_LABEL = yes;
-      NFS_LOCALIO           = whenAtLeast "6.12" yes;
+
+      # Fails with
+      # `fs/nfs/localio.o: relocation R_AARCH64_ADR_PREL_PG_HI21 against symbol `nfs_to' which may bind externally can not be used when making a shared object; recompile with -fPIC`
+      NFS_LOCALIO           = lib.mkIf (!stdenv.hostPlatform.isAarch64) (whenAtLeast "6.12" yes);
 
       CIFS_XATTR        = yes;
       CIFS_POSIX        = option yes;