Run kexec/kdump cases on printk tree

Recently we got kdump hang problems reported by different customers, and it finally points to printk's atomic console change causing them. So apply for adding PRINTK maintainers' tree in upstream kernel to CKI and run kexec/kdump test cases on that. Needed information are put at below:

Which kernel tree and branch we should test?
- git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux.git
Which tests should be run?
- Run kexec/kdump test cases
Which architectures or specific HW should we test?
- X86, arm64 (generic architectures)
If DataWarehouse dashboard is not enough, where should we send results?
- It's enough