LU-5396 mdc: (and lmv, mgc, osc) make some functions static

LU-5396 mdc: (and lmv, mgc, osc) make some functions static

Some functions and variables are only used in their C file, so reduce
their scope. This reduces the code size, and fixes sparse warnings
such as:

  warning: symbol 'proc_lnet_routes' was not declared.
      Should it be static?
  warning: symbol 'proc_lnet_routers' was not declared.
      Should it be static?

Some prototypes were removed from C files and added to the proper
header.

Signed-off-by: Frank Zago <fzago@cray.com>
Change-Id: I8dcc5224c1da75cfb5ef7afb1fdb0f72422a3ac0
Reviewed-on: http://review.whamcloud.com/12222
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>