x86/Kconfig: Turn off DEBUG_NX_TEST module in defconfigs

The x86 defconfigs include exactly one module: test_nx.ko, a
special-purpose module which just exists to do evil things like
executing code off the stack to see if the kernel has enabled NX
support.  Anyone who actually uses that module can easily enable
it themselves, but the vast majority of kernel builds don't need
it; disable it by default.

Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Link: http://lkml.kernel.org/r/e72faf875e1172fb1cbec5e6d3cd4122df508a97.1346649518.git.josh@joshtriplett.org


Signed-off-by: Ingo Molnar <mingo@kernel.org>