x86: default corruption check to off, but put parameter default in Kconfig

Default the low memory corruption check to off, but make the default setting of
the memory_corruption_check kernel parameter a config parameter.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --cc arch/x86/Kconfig
Simple merge

diff --cc arch/x86/kernel/setup.c
Simple merge