Sometimes during probing and registration of pn533_i2c
NULL pointer dereference happens.
Reproduced in cycle of inserting and removing pn533_i2c
and pn533 modules.

Backtrace:
[<8004205c>] (__queue_work) from [<80042324>] (queue_work_on+0x50/0x5c)
r10:acdc7c80 r9:8006b330 r8:ac0dfb40 r7:ac50c600 r6:00000004 r5:acbbee40 r4:600f0113
[<800422d4>] (queue_work_on) from [<7f7d5b6c>] (pn533_recv_frame+0x158/0x1fc [pn533])
r7:ffffff87 r6:00000000 r5:acbbee40 r4:acbbee00
[<7f7d5a14>] (pn533_recv_frame [pn533]) from [<7f7df4b8>] (pn533_i2c_irq_thread_fn+0x184/0x)
r6:acb2a000 r5:00000000 r4:acdc7b90
[<7f7df334>] (pn533_i2c_irq_thread_fn [pn533_i2c]) from [<8006b354>] (irq_thread_fn+0x24/0x)
r7:00000000 r6:accde000 r5:ac0dfb40 r4:acdc7c80
...

Seems there is some race condition due registration of
irq handler until all data stuctures that could be needed
are ready. So I re-ordered some ops. After this, problem has gone.

Changes in USB part was not tested, but it should not break
anything.
Signed-off-by: Andrey Rusalin <arusalin@dev.rtsoft.ru>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>