sbin/newfs_hammer: Adjust output of -E

sbin/newfs_hammer: Adjust output of -E

This commit adjusts and aligns output of -E option of
newfs_hammer with the previous line.

It should use vol->type instead of typing "Device" in
lowercase, since this is what the vol->type is really
made for.

===== before this commit
  # newfs_hammer -E -L TEST /dev/da1 /dev/da2 /dev/da3
  Volume 0 DEVICE /dev/da1        size 111.79GB
  Trimming Device:/dev/da1, sectors (0 -234441648)
  Volume 1 DEVICE /dev/da2        size 111.79GB
  Trimming Device:/dev/da2, sectors (0 -234441648)
  Volume 2 DEVICE /dev/da3        size 111.79GB
  Trimming Device:/dev/da3, sectors (0 -234441648)
  ...

===== with this commit, looks more sane
  # newfs_hammer -E -L TEST /dev/da1 /dev/da2 /dev/da3
  Volume 0 DEVICE /dev/da1        size 111.79GB
  Trimming DEVICE /dev/da1, sectors (0 -234441648)
  Volume 1 DEVICE /dev/da2        size 111.79GB
  Trimming DEVICE /dev/da2, sectors (0 -234441648)
  Volume 2 DEVICE /dev/da3        size 111.79GB
  Trimming DEVICE /dev/da3, sectors (0 -234441648)
  ...