Make lsdev -v output line up in neat columns by using a fixed width for

Make lsdev -v output line up in neat columns by using a fixed width for
the size field and a tab between the partition type and the size.

Changes this

  disk devices:
        disk0 (MMC)
        disk0s1: DOS/Windows            49MB
        disk0s2: FreeBSD                14GB
        disk0s2a: FreeBSD UFS         14GB
        disk0s2b: Unknown             2048KB
        disk0s2d: FreeBSD UFS         2040KB

to this

  disk devices:
        disk0 (MMC)
        disk0s1: DOS/Windows      49MB
        disk0s2: FreeBSD          14GB
        disk0s2a: FreeBSD UFS     14GB
        disk0s2b: Unknown       2048KB
        disk0s2d: FreeBSD UFS   2040KB