mfd: lpc_ich: Remove useless comments in core part

First of all, remove stalled references to datasheets. If someone knows
the document numbers, it would be added later.

Second, remove FSF snail address since it's subject to change. Actual
information can be found on FSF site on the internet.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>