leds: fix bug with reading NAS SS4200 dmi code

leds: fix bug with reading NAS SS4200 dmi code

While running randconfg with ktest.pl I stumbled upon this bug:

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000003
  IP: [<ffffffff815fe44f>] strstr+0x39/0x86
  PGD 0
  Oops: 0000 [#1] SMP
  last sysfs file:
  CPU 0
  Modules linked in:

  Pid: 1, comm: swapper Not tainted 2.6.37-rc1-test+ #6 DG965MQ/
  RIP: 0010:[<ffffffff815fe44f>]  [<ffffffff815fe44f>] strstr+0x39/0x86
  RSP: 0018:ffff8800797cbd80  EFLAGS: 00010213
  RAX: 0000000000000000 RBX: 0000000000000003 RCX: ffffffffffffffff
  RDX: 0000000000000000 RSI: ffffffff82eb7ac9 RDI: 0000000000000003
  RBP: ffff8800797cbda0 R08: ffff880000000003 R09: 0000000000030725
  R10: ffff88007d294c00 R11: 0000000000014c00 R12: 0000000000000020
  R13: ffffffff82eb7ac9 R14: ffffffffffffffff R15: ffffffff82eb7b08
  FS:  0000000000000000(0000) GS:ffff88007d200000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
  CR2: 0000000000000003 CR3: 0000000002a1d000 CR4: 00000000000006f0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
  Process swapper (pid: 1, threadinfo ffff8800797ca000, task ffff8800797d0000)
  Stack:
   00000000000000ba ffffffff82eb7ac9 ffffffff82eb7ab8 00000000000000ba
   ffff8800797cbdf0 ffffffff81e2050f ffff8800797cbdc0 00000000815f913b
   ffff8800797cbe00 ffffffff82eb7ab8 0000000000000000 0000000000000000
  Call Trace:
   [<ffffffff81e2050f>] dmi_matches+0x117/0x154
   [<ffffffff81e205d7>] dmi_check_system+0x3d/0x8d
   [<ffffffff82e1ad25>] ? nas_gpio_init+0x0/0x2c8
   [<ffffffff82e1ad49>] nas_gpio_init+0x24/0x2c8
   [<ffffffff820d750d>] ? wm8350_led_init+0x0/0x20
   [<ffffffff82e1ad25>] ? nas_gpio_init+0x0/0x2c8
   [<ffffffff810022f7>] do_one_initcall+0xab/0x1b2
   [<ffffffff82da749c>] kernel_init+0x248/0x331
   [<ffffffff8100e624>] kernel_thread_helper+0x4/0x10
   [<ffffffff82da7254>] ? kernel_init+0x0/0x331

Found that the nas_led_whitelist dmi_system_id structure array had no
NULL end delimiter, causing the dmi_check_system() loop to read an
undefined entry.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Dave Hansen <dave@sr71.net>
Acked-by: Richard Purdie <rpurdie@linux.intel.com>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>