mtd: base-files: Unify dual-firmware devices (Linksys)

Consistently handle boot-count reset and upgrade across
ipq40xx, ipq806x, kirkwood, mvebu

Dual-firmware devices often utilize a specific MTD partition
to record the number of times the boot loader has initiated boot.

Most of these devices are NAND, typically with a 2k erase size.
When this code was ported to the ipq40xx platform, the device in hand
used NOR for this partition, with a 16-byte "record" size. As the
implementation of `mtd resetbc` is by-platform, the hard-coded nature
of this change prevented proper operation of a NAND-based device.

* Unified the "NOR" variant with the rest of the Linksys variants

* Added logging to indicate success and failure

* Provided a meaningful return value for scripting

* "Protected" the use of `mtd resetbc` in start-up scripts so that
   failure does not end the boot sequence

* Moved Linksys-specific actions into common `/etc/init.d/bootcount`

For upgrade, these devices need to determine which partition to flash,
as well as set certain U-Boot envirnment variables to change the next
boot to the newly flashed version.

* Moved upgrade-related environment changes out of bootcount

* Combined multiple flashes of environment into single one

* Current-partition detection now handles absence of `boot_part`

Runtime-tested: Linksys EA8300

Signed-off-by: Jeff Kletsky <git-commits@allycomm.com>
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
[checkpatch.pl fixes, traded split strings for 80+ chars per line]

target/linux/ipq806x/base-files/etc/init.d/bootcount

@@ -0,0 +1,13 @@
+#!/bin/sh /etc/rc.common
+
+START=99
+
+start() {
+	. /lib/functions.sh
+
+	case $(board_name) in
+	linksys,ea8500)
+		mtd resetbc s_env || true
+		;;
+	esac
+}

target/linux/ipq806x/base-files/etc/init.d/linksys_recovery

@@ -1,19 +0,0 @@
-#!/bin/sh /etc/rc.common
-# Copyright (C) 2015 OpenWrt.org
-
-START=97
-boot() {
-. /lib/functions.sh
-
-case $(board_name) in
-	linksys,ea8500)
-		# make sure auto_recovery in uboot is always on
-		AUTO_RECOVERY_ENA="`fw_printenv -n auto_recovery`"
-		if [ "$AUTO_RECOVERY_ENA" != "yes" ] ; then
-			fw_setenv auto_recovery yes
-		fi
-		# reset the boot counter
-		mtd resetbc s_env
-		;;
-esac
-}