4.18.y build failure

[Dan Rue <dan.rue@xxxxxxxxxx>]

The following commit in 4.18.y causes the build to fail:
    79764192e1c4 ("printk/nmi: Prevent deadlock when accessing the main log buffer in NMI")

with:
    | kernel/printk/printk_safe.o: In function `vprintk_func':
    | printk_safe.c:(.text+0x51b): undefined reference to `vprintk_store'
    | printk_safe.c:(.text+0x52f): undefined reference to `defer_console_output'

Picking up these from mainline seems to do the trick:
    a338f84dc196 ("printk: Create helper function to queue deferred console handling")
    ba552399954d ("printk: Split the code for storing a message into the log buffer")

Thanks,
Dan