Disable linux-spi driver for now, will be enabled later.

Index: a/Makefile
===================================================================
--- a/Makefile	2012-02-20 20:08:59.000000000 +0100
+++ b/Makefile	2012-02-20 20:09:30.000000000 +0100
@@ -339,7 +339,7 @@
 CONFIG_SATAMV ?= yes
 
 # Enable Linux spidev interface by default. We disable it on non-Linux targets.
-CONFIG_LINUX_SPI ?= yes
+CONFIG_LINUX_SPI ?= no
 
 # Disable wiki printing by default. It is only useful if you have wiki access.
 CONFIG_PRINT_WIKI ?= no