turbostat: Increase output buffer size to accommodate C8-C10

On platforms with C8-C10 support, the additional C-states cause
turbostat to overrun its output buffer of 128 bytes per CPU.  Increase
this to 256 bytes per CPU.

[ As a bugfix, this should go into 3.10; however, since the C8-C10
  support didn't go in until after 3.9, this need not go into any stable
  kernel. ]

Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Cc: Len Brown <len.brown@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>