x86/Sandy Bridge: mark arrays in __init functions as __initconst

Mark static arrays as __initconst so they get removed when the init
sections are flushed.

Reported-by: Mathias Krause <minipli@googlemail.com>
Link: http://lkml.kernel.org/r/75F4BEE6-CB0E-4426-B40B-697451677738@googlemail.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>