iteflash: make use of 256 byte pages when programming over CCD
iteflash: make use of 256 byte pages when programming over CCD

It turns out the write command used by iteflash requires exactly one
flash page to be written at a time. Recent usb_i2c protocol
enhancement allow to pass up to 4K bytes in one transaction. This
patch makes sure that when using CCD exactly one page at a time is
programmed.

Also, there is no point in trying to sync up more than 10 times.

BRANCH=none
BUG=b:75976718
TEST=verified that both servo controlled write, running

   $ make BOARD=dragonegg -j
   $ ./util/flash_ec --board=dragonegg

  and direct write over Cr50, running

   $ make BOARD=dragonegg -j
   $ cd ./build/dragonegg
   $ util/iteflash -c -e -w ec.bin

  succeed.

Change-Id: I39c10389dfcccbb32252d8c42fc54bef96330d3a
Signed-off-by: Vadim Bendebury <5515d6d2d0829cbe0dd0dcf2094aaded06d58514@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1266677
Reviewed-by: Jett Rink <9d4aef0593e6843318d99df31597fb6153b89787@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec