ARM64: Use pr_debug() for CPU hotplug messages Currently, CPU online messages...

ARM64: Use pr_debug() for CPU hotplug messages Currently, CPU online messages are printed using printk(), and CPU offline messages are printed using pr_notice(). It seems rather silly to have the (otherwise symmetric) messages to be printed using different log levels. Change both messages to be printed using pr_debug() to match the ARM implementation, to avoid disparities in log spam on ARM/ARM64 with otherwise identical loglevel settings.

Change-Id: I58ce95c5b76093ee27678de497cf5c4cab4ad3aa
Signed-off-by: Stepan Moskovchenko <stepanm@codeaurora.org>

Original commit: https://github.com/CyanogenMod/android_kernel_asus_msm8916/commit/3340c631ceb948dc80f609b12acf051a2b184078