fix: cpufreqd MSR spam, udev-shim PCI spam, scheme throttle, keymaps dir

- cpufreqd: suppress MSR errors after 1 failure (was 10)
- udev-shim: demote PCI scan failures from WARN to DEBUG
- accessibility/ime/keymapd: throttle EBADF loop with 100ms sleep
- config: create /etc/keymaps directory for keymapd

local/recipes/system/udev-shim/source/src/scheme.rs

@@ -100,7 +100,7 @@ impl UdevScheme {
                 }
             }
             Err(err) => {
-                log::warn!("udev-shim: failed to read /scheme/pci: {err}");
+                log::debug!("udev-shim: failed to read /scheme/pci: {err}");
             }
         }