Input: HIL - fix rwlock recursion bug

Input: HIL - fix rwlock recursion bug

The following bug happens when insmoding hp_sdc_mlc.ko:

    HP SDC MLC: Registering the System Domain Controller's HIL MLC.
    BUG: rwlock recursion on CPU#0, hotplug/1814, 00854734
    Backtrace:
     [<10267560>] _raw_write_lock+0x50/0x88
     [<10104008>] _write_lock_irqsave+0x14/0x24
     [<008537d4>] hp_sdc_mlc_out+0x38/0x25c [hp_sdc_mlc]
     [<0084ebd8>] hilse_donode+0x308/0x470 [hil_mlc]
     [<0084ed80>] hil_mlcs_process+0x40/0x6c [hil_mlc]
     [<10130f80>] tasklet_action+0x78/0xb8
     [<10130cec>] __do_softirq+0x60/0xcc
     [<1010428c>] __lock_text_end+0x38/0x48
     [<10108348>] do_cpu_irq_mask+0xf0/0x11c
     [<1010b068>] intr_return+0x0/0xc

Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>