Initialize the spinlock before using it.

INFO: trying to register non-static key.
the code is fine but needs lockdep annotation.
turning off the locking correctness validator.
CPU: 2 PID: 1 Comm: swapper/0 Not tainted 4.8.0-dwc-bisect #4
Hardware name: Intel Corp. VALLEYVIEW C0 PLATFORM/BYT-T FFD8, BIOS BLAKFF81.X64.0088.R10.1403240443 FFD8_X64_R_2014_13_1_00 03/24/2014
 0000000000000000 ffff8800788ff770 ffffffff8133d597 0000000000000000
 0000000000000000 ffff8800788ff7e0 ffffffff810cfb9e 0000000000000002
 ffff8800788ff7d0 ffffffff8205b600 0000000000000002 ffff8800788ff7f0
Call Trace:
 [<ffffffff8133d597>] dump_stack+0x67/0x90
 [<ffffffff810cfb9e>] register_lock_class+0x52e/0x540
 [<ffffffff810d2081>] __lock_acquire+0x81/0x16b0
 [<ffffffff810cede1>] ? save_trace+0x41/0xd0
 [<ffffffff810d33b2>] ? __lock_acquire+0x13b2/0x16b0
 [<ffffffff810cf05a>] ? __lock_is_held+0x4a/0x70
 [<ffffffff810d3b1a>] lock_acquire+0xba/0x220
 [<ffffffff8136f1fe>] ? byt_gpio_get_direction+0x3e/0x80
 [<ffffffff81631567>] _raw_spin_lock_irqsave+0x47/0x60
 [<ffffffff8136f1fe>] ? byt_gpio_get_direction+0x3e/0x80
 [<ffffffff8136f1fe>] byt_gpio_get_direction+0x3e/0x80
 [<ffffffff813740a9>] gpiochip_add_data+0x319/0x7d0
 [<ffffffff81631723>] ? _raw_spin_unlock_irqrestore+0x43/0x70
 [<ffffffff8136fe3b>] byt_pinctrl_probe+0x2fb/0x620
 [<ffffffff8142fb0c>] platform_drv_probe+0x3c/0xa0
...

Based on the diff it looks like the problem was introduced in
commit 71e6ca61 ("pinctrl: baytrail: Register pin control handling")
but I wasn't able to verify that empirically as the parent commit
just oopsed when I tried to boot it.

Cc: Cristina Ciocan <cristina.ciocan@intel.com>
Cc: stable@vger.kernel.org
Fixes: 71e6ca61 ("pinctrl: baytrail: Register pin control handling")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>