Convert single line fprintf(.../n) to warn_report()

Convert all the single line uses of fprintf(stderr, "warning:"..."\n"...
to use warn_report() instead. This helps standardise on a single
method of printing warnings to the user.

All of the warnings were changed using this command:
  find ./* -type f -exec sed -i \
    's|fprintf(.*".*warning[,:] \(.*\)\\n"\(.*\));|warn_report("\1"\2);|Ig' \
    {} +

Some of the lines were manually edited to reduce the line length to below
80 charecters.

The #include lines were manually updated to allow the code to compile.

Signed-off-by: Alistair Francis <alistair.francis@xilinx.com>
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Max Reitz <mreitz@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Michael Roth <mdroth@linux.vnet.ibm.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: Yongbok Kim <yongbok.kim@imgtec.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com> [mips]
Message-Id: <ae8f8a7f0a88ded61743dff2adade21f8122a9e7.1505158760.git.alistair.francis@xilinx.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

ui/keymaps.c

@@ -141,7 +141,7 @@ static kbd_layout_t *parse_keyboard_layout(const name2keysym_t *table,
                 int keysym;
                 keysym = get_keysym(table, keyname);
                 if (keysym == 0) {
-                    /* fprintf(stderr, "Warning: unknown keysym %s\n", line);*/
+                    /* warn_report("unknown keysym %s", line);*/
                 } else {
                     const char *rest = line + offset + 1;
                     int keycode = strtol(rest, NULL, 0);