When we map memory at boot we print out the ranges of real addresses
that we mapped and the page size that was used.

Currently it's a bit ugly:

  Mapped range 0x0 - 0x2000000000 with 0x40000000
  Mapped range 0x200000000000 - 0x202000000000 with 0x40000000

Pad the addresses so they line up, and print the page size using
actual units, eg:

  Mapped 0x0000000000000000-0x0000000001200000 with 64.0 KiB pages
  Mapped 0x0000000001200000-0x0000000040000000 with 2.00 MiB pages
  Mapped 0x0000000040000000-0x0000000100000000 with 1.00 GiB pages
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>