tty: vt, convert more macros to functions

Namely convert:
* IS_FG -> con_is_fg
* DO_UPDATE -> con_should_update
* CON_IS_VISIBLE -> con_is_visible

DO_UPDATE was a weird name for a yes/no answer, so the new name is
con_should_update.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Thomas Winischhofer <thomas@winischhofer.net>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: linux-usb@vger.kernel.org
Cc: linux-fbdev@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/include/linux/console_struct.h b/include/linux/console_struct.h
index 5fa605c..a12d3f2 100644
--- a/include/linux/console_struct.h
+++ b/include/linux/console_struct.h
@@ -168,6 +168,9 @@
 
 #define CUR_DEFAULT CUR_UNDERLINE
 
-#define CON_IS_VISIBLE(conp) (*conp->vc_display_fg == conp)
+static inline bool con_is_visible(const struct vc_data *vc)
+{
+	return *vc->vc_display_fg == vc;
+}
 
 #endif /* _LINUX_CONSOLE_STRUCT_H */