CHERRY-PICK: Update GEC parameter size

This will make flashrom use EC_LPC_PARAM_SIZE (128) instead of
EC_LPC_FLASH_SIZE_MAX (64) for GEC reads. GEC writes will use
64 bytes. This is to bring flashrom up to date with EC commit bbdc15.

This also fixes a size comparison in gec_lpc so that the insize and
outsize will be checked against EC_LPC_PARAM_SIZE individually.

(Note: EC_LPC is a misnomer, since it applies to both LPC and I2C
interfaces. TODO: cleanup the naming)

BUG=chrome-os-partner:11097
TEST=read from GEC on Snow (I2C) and Link (LPC)

Change-Id: I936e3989a221a1e7b4213d9a8262ffe08d78565a
Reviewed-on: https://gerrit.chromium.org/gerrit/26901
Reviewed-by: David Hendricks <dhendrix@chromium.org>
Tested-by: David Hendricks <dhendrix@chromium.org>
Commit-Ready: David Hendricks <dhendrix@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/27249
Reviewed-by: Bernie Thompson <bhthompson@chromium.org>
Tested-by: Bernie Thompson <bhthompson@chromium.org>