Add Major, Minor and Mkdev functions for converting device numbers to
their major/minor components and vice versa.

Use the respective functions provided by the Solaris libc instead of
reimplementing them.

Test the conversion function with some well-known static device numbers
for devices which should be present on any Solaris system.

Re-generated files on OpenIndiana Hipster 2017.04 (SunOS 5.11) which
also added some previously missing error constants.

Change-Id: Ief9ea973d91c24956571eb8fafc8a4525b0f5b90
Reviewed-on: https://go-review.googlesource.com/64390Reviewed-by: Ian Lance Taylor <iant@golang.org>