Flashrom: Add write-protect support on Skylake

This patch does the following:
1. Adds write-protect using hardware sequencing
   for W25R128FV flash chip.
2. Removes software sequencing in Skylake as it
   is not supported.

BUG=chrome-os-partner:37711
TEST=flashrom -p host --wp-status

flashrom -p host --wp-range 0 0
flashrom -p host --wp-disable
flashrom -p host --wp-enable

Change-Id: I74799e34eb4ae23de5d1cba87af32c3828b44fc8
Signed-off-by: Ramya Vijaykumar <ramya.vijaykumar@intel.com>
Reviewed-on: https://chromium-review.googlesource.com/270304
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Commit-Queue: Wenkai Du <wenkai.du@intel.com>
Tested-by: Wenkai Du <wenkai.du@intel.com>
diff --git a/programmer.h b/programmer.h
index aa0192e..9f3b06b 100644
--- a/programmer.h
+++ b/programmer.h
@@ -265,6 +265,7 @@
 /* chipset_enable.c */
 int chipset_flash_enable(void);
 int get_target_bus_from_chipset(enum chipbustype *target_bus);
+enum ich_chipset ich_generation;
 
 /* processor_enable.c */
 int processor_flash_enable(void);