src: Rename 'ich_generation' to 'g_ich_generation'

The state of 'ich_generation' can be hard to follow where it is
currently global. Rename where appropriate to delinate the global state
from the local state passed in as an argument.

BRANCH=None
BUG=b:139255749
TEST=built

Change-Id: I07f6a6f52d8eeb4d3373ea08e5637f345633dfbc
Signed-off-by: Edward O'Callaghan <quasisec@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/flashrom/+/1781978
Reviewed-by: Sam McNally <sammc@chromium.org>
Reviewed-by: Andrew McRae <amcrae@chromium.org>
diff --git a/programmer.h b/programmer.h
index a6c3c7c..1aed65c 100644
--- a/programmer.h
+++ b/programmer.h
@@ -628,7 +628,7 @@
  * device. When running on non-intel platforms default value of
  * CHIPSET_ICH_UNKNOWN is used.
 */
-extern enum ich_chipset ich_generation;
+extern enum ich_chipset g_ich_generation;
 
 /*
  * This global variable is set to indicate that the invoked flash programming