Use root.fs on qemu as well

We had lots of duplication of code between root.fs and fdt.fs

The reason we didn't use root.fs in the first place is that it tried
to create the root node and the chosen node which we already have via
the fdt.

Instead, modify root.fs to check for their presence and only "extend"
them in that case.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

board-qemu/slof/OF.fs

@@ -109,10 +109,14 @@ d# 512000000 VALUE tb-frequency   \ default value - needed for "ms" to work
 
 #include <scsi-loader.fs>
 
-360 cp
+340 cp
 
 #include "fdt.fs"
 
+360 cp
+
+#include <root.fs>
+
 370 cp
 
 \ Grab rtas from qemu

board-qemu/slof/fdt.fs

@@ -361,43 +361,3 @@ fdt-claim-reserve
 ;
 s" /" find-node fdt-fix-phandles
 
-
-\ Remaining bits from root.fs
-
-defer (client-exec)
-defer client-exec
-
-\ defined in slof/fs/client.fs
-defer callback
-defer continue-client
-
-: set-chosen ( prop len name len -- )
-  s" /chosen" find-node set-property ;
-
-: get-chosen ( name len -- [ prop len ] success )
-  s" /chosen" find-node get-property 0= ;
-
-" /" find-device
-
-new-device
-  s" aliases" device-name
-finish-device
-
-new-device
-  s" options" device-name
-finish-device
-
-new-device
-  s" openprom" device-name
-  s" BootROM" device-type
-finish-device
-
-new-device 
-#include <packages.fs>
-finish-device
-
-: open true ;
-: close ;
-
-device-end
-

slof/fs/root.fs

@@ -25,33 +25,51 @@ defer continue-client
 : get-chosen ( name len -- [ prop len ] success )
   s" /chosen" find-node get-property 0= ;
 
-new-device
-  s" /" device-name
-  new-device
+\ Look for an exising root, create one if needed
+" /" find-node dup 0= IF
+    drop
+    new-device
+    s" /" device-name
+ELSE
+    extend-device
+THEN
+
+\ Create /chosen if it doesn't exist
+" /chosen" find-node dup 0= IF
+    drop
+    new-device
     s" chosen" device-name
-    s" " encode-string s" bootargs" property
-    s" " encode-string s" bootpath" property
-  finish-device
+ELSE
+    extend-device
+THEN
+s" " encode-string s" bootargs" property
+s" " encode-string s" bootpath" property
+finish-device
 
-  new-device
+\ Create /aliases
+new-device
     s" aliases" device-name
-  finish-device
+finish-device
 
-  new-device
+\ Create /options
+new-device
     s" options" device-name
-  finish-device
+finish-device
 
-
-  new-device
+\ Create /openprom
+new-device
     s" openprom" device-name
     s" BootROM" device-type
-  finish-device
+finish-device
 
-  new-device 
+\ Create /packages
+new-device 
 #include <packages.fs>
-  finish-device
+finish-device
 
 : open true ;
 : close ;
 
+\ Finish root
 finish-device
+