remove Documentation/smp.txt

After seeing the filename I'd have expected something about the
implementation of SMP in the Linux kernel - not some notes on kernel
configuration and building trivialities noone would search at this
place.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Acked-by: Alan Cox <alan@redhat.com>
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 36a4018..223eb15 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -1754,8 +1754,8 @@
 	  People using multiprocessor machines who say Y here should also say
 	  Y to "Enhanced Real Time Clock Support", below.
 
-	  See also the <file:Documentation/smp.txt> and the SMP-HOWTO
-	  available at <http://www.tldp.org/docs.html#howto>.
+	  See also the SMP-HOWTO available at
+	  <http://www.tldp.org/docs.html#howto>.
 
 	  If you don't know what to do here, say N.