ACPI / proc: Do not say when /proc interfaces will be deleted in Kconfig

Do not tell people in the Kconfig help when exactly we are going to
remove the deprecated ACPI interfaces in /proc, because, honestly,
we don't know.  We will remove them when they are not used any more.

In particular, do not tell them that the interfaces will be removed
in a kernel release that already happened long ago.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/Kconfig

@@ -60,7 +60,7 @@ config ACPI_PROCFS_POWER
 	  This option has no effect on /proc/acpi/ directories
 	  and functions, which do not yet exist in /sys
 	  This option, together with the proc directories, will be
-	  deleted in 2.6.39.
+	  deleted in the future.
 
 	  Say N to delete power /proc/acpi/ directories that have moved to /sys/