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.

Corresponding to flashrom svn r1841.

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

cli_output.c

@@ -25,6 +25,9 @@
 #include <errno.h>
 #include "flash.h"
 
+int verbose_screen = MSG_INFO;
+int verbose_logfile = MSG_DEBUG2;
+
 #ifndef STANDALONE
 static FILE *logfile = NULL;