mp2usb: finish the removal

- remove from boards.cfg
- add to doc/README.scrapyard

Signed-off-by: Eric Bénard <eric@eukrea.com>

boards.cfg

@@ -58,7 +58,6 @@ cmc_pu2                      arm         arm920t     -                   -
 csb637                       arm         arm920t     -                   -              at91rm9200
 kb9202                       arm         arm920t     -                   -              at91rm9200
 m501sk                       arm         arm920t     -                   -              at91rm9200
-mp2usb                       arm         arm920t     -                   -              at91rm9200
 at91rm9200dk                 arm         arm920t     -                   atmel          at91rm9200
 mx1ads                       arm         arm920t     -                   -              imx
 mx1fs2                       arm         arm920t     -                   -              imx

doc/README.scrapyard

@@ -11,6 +11,7 @@ easily if here is something they might want to dig for...
 
 Board	Arch	CPU	removed	    Commit	last known maintainer/contact
 =============================================================================
+mp2usb	ARM	AT91RM2900 	ee986e2	2011-01-25	Eric Bénard <eric@eukrea.com>
 barco	powerpc	MPC8245	-	  2010-11-23	Marc Leeman <marc.leeman@barco.com>
 ERIC	powerpc	405GP	d9ba451	  2010-11-21	Swen Anderson <sand@peppercon.de>
 VoVPN-GW_100MHz	powerpc	MPC8260 26fe3d2 2010-10-24	Juergen Selent <j.selent@elmeg.de>