[TRIVIAL] Remove x86 instructions on alpha.

From <adobriyan@mail.ru>.

arch/alpha/Kconfig

@@ -486,19 +486,8 @@ config SMP
 	  singleprocessor machines. On a singleprocessor machine, the kernel
 	  will run faster if you say N here.
 
-	  Note that if you say Y here and choose architecture "586" or
-	  "Pentium" under "Processor family", the kernel will not work on 486
-	  architectures. Similarly, multiprocessor kernels for the "PPro"
-	  architecture may not work on all Pentium based boards.
-
-	  People using multiprocessor machines who say Y here should also say
-	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
-	  Management" code will be disabled if you say Y here.
-
-	  See also the <file:Documentation/smp.tex>,
-	  <file:Documentation/smp.txt>, <file:Documentation/i386/IO-APIC.txt>,
-	  <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
-	  <http://www.tldp.org/docs.html#howto>.
+	  See also the <file:Documentation/smp.tex>, and the SMP-HOWTO
+	  available at <http://www.tldp.org/docs.html#howto>.
 
 	  If you don't know what to do here, say N.