defconfig: disable CONFIG_DEBUG_SPINLOCK

This debug option costs around 5 MBytes of RAM and can be safely removed
as our 3.10 kernel is stable enough now. As CONFIG_SPLIT_PTLOCK_CPUS is
depending of this one, its value is set back automatically to default (4).

Change-Id: Ic218dd58152fe0a22f0e195dd835130d509f262f
Tracked-On: https://jira01.devtools.intel.com/browse/AW-4638


Signed-off-by: Simon Dubray <simonx.dubray@intel.com>
Reviewed-on: https://android.intel.com/572652


Reviewed-by: jenkins_ndg <jenkins_ndg@intel.com>
Reviewed-by: Zaghdoud, WalidX <walidx.zaghdoud@intel.com>
Reviewed-by: Nassiet, GaelleX <gaellex.nassiet@intel.com>
Reviewed-by: Viel, ClementX <clementx.viel@intel.com>
Tested-by: Viel, ClementX <clementx.viel@intel.com>
Reviewed-by: Deverge, Jean-francoisX <jean-francoisx.deverge@intel.com>
Reviewed-by: Whitfield, MichaelX <michaelx.whitfield@intel.com>
Reviewed-by: Tasayco Loarte, VictorX <victorx.tasayco.loarte@intel.com>
Reviewed-by: Ledentec, AlexandreX <alexandrex.ledentec@intel.com>