spi_fpga_fw: fix access uninitialized spin_lock bug

spi_fpga_fw: fix access uninitialized spin_lock bug

fix this bug:
BUG: spinlock bad magic on CPU#0, swapper/1
lock: c0c83ffc, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
[<c044f108>] (unwind_backtrace+0x0/0xdc) from [<c06f39e0>] (dump_stack+0x18/0x1c)
[<c06f39e0>] (dump_stack+0x18/0x1c) from [<c055aaa8>] (spin_bug+0x90/0xa4)
[<c055aaa8>] (spin_bug+0x90/0xa4) from [<c055abf0>] (_raw_spin_lock+0x2c/0x168)
[<c055abf0>] (_raw_spin_lock+0x2c/0x168) from [<c06f6f84>] (_spin_lock_irqsave+0x5c/0x68)
[<c06f6f84>] (_spin_lock_irqsave+0x5c/0x68) from [<c0418a78>] (fpga_dl_fw+0x98/0x358)
[<c0418a78>] (fpga_dl_fw+0x98/0x358) from [<c040da68>] (machine_rk2818_board_init+0x94/0x124)
[<c040da68>] (machine_rk2818_board_init+0x94/0x124) from [<c040a8c8>] (customize_machine+0x20/0x2c)
[<c040a8c8>] (customize_machine+0x20/0x2c) from [<c0449364>] (do_one_initcall+0x64/0x1c0)
[<c0449364>] (do_one_initcall+0x64/0x1c0) from [<c04085f4>] (kernel_init+0xa4/0x11c)
[<c04085f4>] (kernel_init+0xa4/0x11c) from [<c044a8fc>] (kernel_thread_exit+0x0/0x8)