ARM: fiq_debugger: fix uninitialised spin_lock.

Backtrace:
[<c0045ea0>] (dump_backtrace+0x0/0x10c) from [<c0575c60>] (dump_stack+0x1)
 r6:c07a489c r5:c0c9b9dc r4:00000002 r3:271aed3b
[<c0575c48>] (dump_stack+0x0/0x1c) from [<c00b1b00>] (__lock_acquire+0x93)
[<c00b11c8>] (__lock_acquire+0x0/0xad4) from [<c00b219c>] (lock_acquire+0)
[<c00b210c>] (lock_acquire+0x0/0xa4) from [<c057e544>] (_raw_spin_lock_ir)
[<c057e4f8>] (_raw_spin_lock_irq+0x0/0x5c) from [<c005297c>] (fiq_tty_wri)
 r5:e30f0000 r4:e36f0c00
[<c005293c>] (fiq_tty_write+0x0/0x80) from [<c023168c>] (n_tty_write+0x18)
 r8:e370fc40 r7:e378a000 r6:e3572d1c r5:e36f0c00 r4:00000002
r3:c005293c
[<c0231500>] (n_tty_write+0x0/0x440) from [<c022d4a4>] (tty_write+0x100/0)
[<c022d3a4>] (tty_write+0x0/0x2a8) from [<c0100b80>] (vfs_write+0xa4/0x14)
[<c0100adc>] (vfs_write+0x0/0x148) from [<c0100cdc>] (sys_write+0x40/0x78)
 r8:00000002 r7:4076d2c4 r6:e370fc40 r5:00000000 r4:00000000
[<c0100c9c>] (sys_write+0x0/0x78) from [<c0041740>] (ret_fast_syscall+0x0)
 r8:c0041908 r7:00000004 r6:00000002 r5:00000000 r4:4007cbe0

[ccross: moved spin_lock_init into existing #ifdef]
Change-Id: If400d084eb20433c126ea1dd027a6be7f2ebb1f6
Signed-off-by: Mars <caoziqiang@meizu.com>
Signed-off-by: Colin Cross <ccross@android.com>