Refactor some CLI-relevant parts.

Begin to move functions that clearly belong to the (command line)
user interface out of flashrom's core files like flashrom.c.

 - Refine messages within check_chip_supported(), rename it to
   print_chip_support_status() and move it to newly created cli_common.c.
 - Move flashbuses_to_text() to cli_common.c as well.
 - Move global verbosity variables to cli_output.c.

Signed-off-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
Acked-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>

git-svn-id: svn://flashrom.org/flashrom/trunk@1841 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1