ia64: fix typo in a comment

s/when when/when/

Link: https://lkml.kernel.org/r/20210817112500.12848-1-wangborong@cdjrlc.comSigned-off-by: Jason Wang <wangborong@cdjrlc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/ia64/kernel/acpi.c

@@ -906,6 +906,6 @@ EXPORT_SYMBOL(acpi_unregister_ioapic);
 /*
  * acpi_suspend_lowlevel() - save kernel state and suspend.
  *
- * TBD when when IA64 starts to support suspend...
+ * TBD when IA64 starts to support suspend...
  */
 int acpi_suspend_lowlevel(void) { return 0; }