Linux 6.9 Cleans Up Printk Code While Preparing For Atomic Consoles

The Linux work around atomic consoles and threaded printing remains ongoing. This work is particularly interesting as it's the last major blocker before real-time "RT" kernel support can land. This work sadly isn't ready for the new Linux 6.9 cycle but at least some printk clean-ups are landing for issues discovered during the atomic consoles effort...