zfs: simplify kernelIsCompatible function (#510656)

      ];

      kernelIsCompatible =

        kernel:

        let

          nextMajorMinor =

            ver:

            "${lib.versions.major ver}.${

              lib.pipe ver [

                lib.versions.minor

                lib.toInt

                (x: x + 1)

                toString

              ]

            }";

        in

        (lib.versionAtLeast kernel.version kernelMinSupportedMajorMinor)

        && (lib.versionOlder kernel.version (nextMajorMinor kernelMaxSupportedMajorMinor));

        && (lib.versionAtLeast kernelMaxSupportedMajorMinor (lib.versions.majorMinor kernel.version));

      # XXX: You always want to build kernel modules with the same stdenv as the

      # kernel was built with. However, since zfs can also be built for userspace we