Kobo: Yet another attempt at working around the hangs on the latest NXP boards (#10771)

* Notification: Drop the fencing from #10083; it never actually helped, and had subtle side-effects we could do without.
* VirtualKeyBoard: Flash on close, otherwise, some of the fast refresh glitches may be burned into the working buffer until a flash. Making sure we flash ourselves prevent it from sticking around on the page ;).
* util: Move `writeToSysfs` to base (i.e., `ffi/util`), as we need it there (and it actually makes more sense there anyway ;p).
* Bump base for https://github.com/koreader/koreader-base/pull/1645, which is where the actual workaround (hopefully) lives.

Re #8414, #9806, #10558

frontend/ui/data/onetime_migration.lua

@@ -8,7 +8,7 @@ local logger = require("logger")
 local _ = require("gettext")
 
 -- Date at which the last migration snippet was added
-local CURRENT_MIGRATION_DATE = 20230710
+local CURRENT_MIGRATION_DATE = 20230731
 
 -- Retrieve the date of the previous migration, if any
 local last_migration_date = G_reader_settings:readSetting("last_migration_date", 0)
@@ -585,5 +585,17 @@ if last_migration_date < 20230710 then
     end
 end
 
+-- 20230731, aka., "let's kill all those stupid and weird mxcfb workarounds"
+if last_migration_date < 20230731 then
+    logger.info("Performing one-time migration for 20230731")
+
+    local Device = require("device")
+    if Device:isKobo() then
+        if not Device:hasReliableMxcWaitFor() then
+            G_reader_settings:delSetting("followed_link_marker")
+        end
+    end
+end
+
 -- We're done, store the current migration date
 G_reader_settings:saveSetting("last_migration_date", CURRENT_MIGRATION_DATE)