commit 361e9dfb upstream.

The buffers sized by CONFIG_LOG_BUF_SHIFT and
CONFIG_LOG_CPU_MAX_BUF_SHIFT do not exist if CONFIG_PRINTK=n, so don't
ask about their size at all.
Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
[ kamal: backport to 3.13-stable: only LOG_BUF_SHIFT ]
Signed-off-by: Kamal Mostafa <kamal@canonical.com>