ar71xx: Fix sysupgrades for Allnet and OpenMesh devices

Both Allnet and OpenMesh sysupgrade uses fw_setenv from uboot-envtools to
change different settings in the uboot environment. uboot-envtools version
2013.01 introduced a filesystem lock "/var/lock/fw_printenv.lock" to guarantee
mutually exclusive access to the uboot environment. But the path /var doesn't
exist on the sysupgrade ramfs.

An upgrade on these devices fails since r36033 ("[package] uboot-envtools:
upgrade to version 2013.01.01") with following messages:

 Error opening lock file /var/lock/fw_printenv.lock
 failed to update U-Boot environment

Creating the "/var/lock" path before running fw_setenv is therefore a
requirement unless the locking functionality in fw_setenv is removed or
replaced with optional locking.

Signed-off-by: Sven Eckelmann <sven@open-mesh.com>
Signed-off-by: Gabor Juhos <juhosg@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@38483 3c298f89-4303-0410-b956-a3cf2f4a3e73
mkfwimage: Increase RSPRO maximum size to 0xF00000 (15 MiB)

RSPRO has 16MiB of Flash, using the following layout:

[    2.930000] 0x000000000000-0x000000030000 : "RedBoot"
[    2.940000] 0x000000030000-0x000000130000 : "kernel"
[    2.950000] 0x000000130000-0x000000ff0000 : "rootfs"
[    2.960000] 0x000000ff0000-0x000000fff000 : "FIS directory"
[    2.970000] 0x000000fff000-0x000001000000 : "RedBoot config"

Firmware images contain kernel and rootfs, so they can use up to 0xFF0000 -
0x30000 = 0xFC0000 (15,75MiB) of space. We don't include the RedBoot and FIS
partitions and leave an extra 0xC0000 (768KiB) of space.

This is based on revision 18410 which sets the limit to 0xB00000 (11 MiB).

Signed-off-by: Bruno Randolf <br1@einfach.org>
Signed-off-by: Gabor Juhos <juhosg@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@38484 3c298f89-4303-0410-b956-a3cf2f4a3e73