x86/docs: remove noirqbalance param docs

Impact: documentation fix

irqbalance was removed by:

  commit 8b8e8c1bf7275eca859fe551dfa484134eaf013b
  Author: Yinghai Lu <yhlu.kernel@gmail.com>
  Date:   Tue Aug 19 20:50:23 2008 -0700

Remove the associated documentation for noirqbalance.

Signed-off-by: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Documentation/kernel-parameters.txt

@@ -1470,8 +1470,6 @@ and is between 256 and 4096 characters. It is defined in the file
 			Valid arguments: on, off
 			Default: on
 
-	noirqbalance	[X86-32,SMP,KNL] Disable kernel irq balancing
-
 	noirqdebug	[X86-32] Disables the code which attempts to detect and
 			disable unhandled interrupt sources.