x86/config: Make the x86 defconfigs a bit more usable

 - Use 'make savedefconfig' to refresh & regenerate the files
 - Add in KVM boot enablers
 - Enable the cgroup features most distros rely on

[ fix bug found by Nathan Chancellor ]

Acked-by: Nathan Chancellor <nathan@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/YjwsUT/6PkRPjnHE@gmail.com