Move erase verification to generic code

Erase functions are no longer called from chip drivers and thus their
internal erase verification can be moved to generic code. This also
makes it easier to skip the verify step if desired and to differentiate
between failed command submission and failed erase verification.

Corresponding to flashrom svn r1353.

Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Acked-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
diff --git a/flashrom.c b/flashrom.c
index 6979d84..13dd581 100644
--- a/flashrom.c
+++ b/flashrom.c
@@ -1400,6 +1400,10 @@
 		ret = erasefn(flash, start, len);
 		if (ret)
 			return ret;
+		if (check_erased_range(flash, start, len)) {
+			msg_cerr("ERASE FAILED!\n");
+			return -1;
+		}
 		/* Erase was successful. Adjust curcontents. */
 		memset(curcontents, 0xff, len);
 		skip = 0;