ceph-volume: include LVM mapper devices in get_devices()

ceph-volume: include LVM mapper devices in get_devices()

`ceph-volume inventory --list-all` doesn't include LVs devices:

```
NAME          MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
vda           253:0    0   61G  0 disk
└─vda1        253:1    0   61G  0 part /etc/ceph/ceph.keyring
                                       /etc/ceph/ceph.conf
                                       /run/podman-init
                                       /rootfs/var/lib/containers/storage/overlay
                                       /rootfs
vdb           253:16   0  200G  0 disk
vdc           253:32   0  200G  0 disk
vdd           253:48   0  200G  0 disk
vde           253:64   0  200G  0 disk
vdf           253:80   0  200G  0 disk
vdg           253:96   0  200G  0 disk
vdh           253:112  0  200G  0 disk
vdi           253:128  0  200G  0 disk
vdj           253:144  0  200G  0 disk
vdk           253:160  0  200G  0 disk
└─vg_test-lv1 252:0    0  200G  0 lvm

Device Path               Size         Device nodes    rotates available
Model name
/dev/vdb                  200.00 GB    vdb             True    True
/dev/vdc                  200.00 GB    vdc             True    True
/dev/vdd                  200.00 GB    vdd             True    True
/dev/vde                  200.00 GB    vde             True    True
/dev/vdf                  200.00 GB    vdf             True    True
/dev/vdg                  200.00 GB    vdg             True    True
/dev/vdh                  200.00 GB    vdh             True    True
/dev/vdi                  200.00 GB    vdi             True    True
/dev/vdj                  200.00 GB    vdj             True    True
/dev/vda                  61.00 GB     vda             True    False
/dev/vda1                 61.00 GB     vda             False   False
/dev/vdk                  200.00 GB    vdk             True    False
```

This commit removes the UdevData(diskname).is_lvm check so LVs devices
are no longer skipped when listing devices.

```

Device Path               Size         Device nodes    rotates available
Model name
/dev/vdb                  200.00 GB    vdb             True    True
/dev/vdc                  200.00 GB    vdc             True    True
/dev/vdd                  200.00 GB    vdd             True    True
/dev/vde                  200.00 GB    vde             True    True
/dev/vdf                  200.00 GB    vdf             True    True
/dev/vdg                  200.00 GB    vdg             True    True
/dev/vdh                  200.00 GB    vdh             True    True
/dev/vdi                  200.00 GB    vdi             True    True
/dev/vdj                  200.00 GB    vdj             True    True
/dev/vda                  61.00 GB     vda             True    False
/dev/vda1                 61.00 GB     vda             False   False
/dev/vdk                  200.00 GB    vdk             True    False
/dev/vg_test/lv1          200.00 GB    vdk             True    False
```

Fixes: https://tracker.ceph.com/issues/74775
Signed-off-by: Guillaume Abrioux <gabrioux@ibm.com>