Restore Nokia support in seattleinstaller

[aaaaalbert]

24cf396 removed support for Nokia N800/N900 devices in favor of RaspberryPi. We should figure out how to tell Nokias and RasPi's apart using their uname, platform, procfs entries etc. (they share the arm processor, making the original simple check unusable).

Monzur kindly provided a few details for a Nokia N800:

python version = 2.5.2
sys.platform = linux2
os.name = posix
platform.platform() = Linux-2.6.21-omap1-armv61-with-debian-testing-unstable
platform.uname() = ('Linux', 'Nokia-N800-43-7', '2.6.21-omap1', '#2 Tue Oct 14 11:25:25 EEST 2008', 'armv61', '')

/proc/version = "Linux version 2.6.21-omap1 (root@bifh) (gcc version 3.4.4 (release) (CodeSourcery ARM 2005q3-2)) #2 Tue Oct 14 11:25:25 EEST 2008
/proc/sys/kernel/hostname = "Nokia-N800-43-7"

/proc/cpuinfo =
"Processor       : ARMv6-compatible processor rev 2 (v6l)
BogoMIPS        : 164.36
Features        : swp half thumb fastmult vfp edsp java
CPU implementer : 0x41
CPU architecture: 6TEJ
CPU variant     : 0x0
CPU part        : 0xb36
CPU revision    : 2
Cache type      : write-back
Cache clean     : cp15 c7 ops
Cache lockdown  : format C
Cache format    : Harvard
I size          : 32768
I assoc         : 4
I line length   : 32
I sets          : 256
D size          : 32768
D assoc         : 4
D line length   : 32
D sets          : 256

Hardware        : Nokia N800
Revision        : 24202524
Serial          : 0000000000000000"

[aaaaalbert]

Judging from a couple of cpuinfos for N900's floating around the web, it seems that a "Hardware" line of /proc/cpuinfo containing "Nokia" can be considered a hit:

• "Nokia RX-51 board" (http://talk.maemo.org/archive/index.php/t-46314.html, http://www.natisbad.org/N900/n900-commented-hardware-specs.html)
• "Nokia RX-44" (http://talk.maemo.org/archive/index.php/t-43189.html)

[aaaaalbert]

See also #118.