ARM: ns9750dev: remove remainders of dead board

Commit 8b710b1 started removing code for the unmaintained "ns9750dev"
board; the board support is still broken, and not included anywhere in
the Makefile or boards.cfg.  Remove the remaining dead code.

Signed-off-by: Wolfgang Denk <wd@denx.de>
diff --git a/doc/README.ns9750dev b/doc/README.ns9750dev
deleted file mode 100644
index 2991440..0000000
--- a/doc/README.ns9750dev
+++ /dev/null
@@ -1,36 +0,0 @@
-U-Boot Port to the NS9750 DevKit from NetSilicon
-
-1 Overview
-2 Board Configuration
-3 Installation
-
-
-1 Overview
-----------
-
-This port supports these NS9750 features.
-
-o one UART
-
-2 Board Configuration
----------------------
-
-Switches:
-SW10: 4
-SW11: 6,7
-SW16: 6,7,8
-SW17-SW20: 1
-SW4: 3, 6
-SW 1: 1
-SW2: 4
-SW3: 3
-SW8: 3 (rotated by 180 degree!!!!)
-
-Serial Console is Port B (bottom right port)
-
-3 Installation
---------------
-
-Have fun,
---
-Markus Pietrek <mpietrek@fsforth.de>
diff --git a/doc/README.scrapyard b/doc/README.scrapyard
index 185bd0e..e9ca96c 100644
--- a/doc/README.scrapyard
+++ b/doc/README.scrapyard
@@ -11,6 +11,7 @@
 
 Board            Arch        CPU            Commit      Removed     Last known maintainer/contact
 =================================================================================================
+ns9750dev        arm         arm926ejs      -           -           Markus Pietrek <mpietrek@fsforth.de>
 AMX860           powerpc     mpc860         1b0757e     2012-10-28  Wolfgang Denk <wd@denx.de>
 c2mon            powerpc     mpc855         1b0757e     2012-10-28  Wolfgang Denk <wd@denx.de>
 ETX094           powerpc     mpc850         1b0757e     2012-10-28  Wolfgang Denk <wd@denx.de>
diff --git a/doc/driver-model/UDM-serial.txt b/doc/driver-model/UDM-serial.txt
index c6a8ab0..ef71fea 100644
--- a/doc/driver-model/UDM-serial.txt
+++ b/doc/driver-model/UDM-serial.txt
@@ -86,7 +86,7 @@
 
   7) ns9750_serial.c
   ------------------
-  No support for CONFIG_SERIAL_MULTI. Simple conversion possible.
+  Unmaintained port. Code got removed.
 
   8) opencores_yanu.c
   -------------------