Documentation: remove outdated references to the linux-next wiki

The linux-next wiki at http://linux.f-seidel.de/linux-next/pmwiki has
been gone for several months now.
Signed-off-by: NJim Davis <jim.epost@gmail.com>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

Documentation/HOWTO

@@ -324,7 +324,6 @@ tree, they need to be integration-tested.  For this purpose, a special
 testing repository exists into which virtually all subsystem trees are
 pulled on an almost daily basis:
 	http://git.kernel.org/?p=linux/kernel/git/next/linux-next.git
-	http://linux.f-seidel.de/linux-next/pmwiki/
 
 This way, the -next kernel gives a summary outlook onto what will be
 expected to go into the mainline kernel at the next merge period.

Documentation/development-process/2.Process

@@ -289,10 +289,6 @@ lists when they are assembled; they can be downloaded from:
 
 	http://www.kernel.org/pub/linux/kernel/next/
 
-Some information about linux-next has been gathered at:
-
-	http://linux.f-seidel.de/linux-next/pmwiki/
-
 Linux-next has become an integral part of the kernel development process;
 all patches merged during a given merge window should really have found
 their way into linux-next some time before the merge window opens.

Documentation/development-process/8.Conclusion

@@ -22,10 +22,6 @@ Beyond that, a valuable resource for kernel developers is:
 
 	http://kernelnewbies.org/
 
-Information about the linux-next tree gathers at:
-
-	http://linux.f-seidel.de/linux-next/pmwiki/
-
 And, of course, one should not forget http://kernel.org/, the definitive
 location for kernel release information.