The SCU message's data field used for receiving response data from SCU
should be 32-bit width, as SCU will send back 32-bit width data.

This solves kernel panic when CONFIG_CC_HAVE_STACKPROTECTOR_SYSREG is
enabled.

[    1.950768] Kernel panic - not syncing: stack-protector: Kernel stack is corrupted
[    1.980607] Workqueue: events imx_sc_check_for_events
[    1.985657] Call trace:
[    1.988104]  dump_backtrace+0x0/0x140
[    1.991768]  show_stack+0x14/0x20
[    1.995090]  dump_stack+0xb4/0xf8
[    1.998407]  panic+0x158/0x324
[    2.001463]  print_tainted+0x0/0xa8
[    2.004950]  imx_sc_check_for_events+0x18c/0x190
[    2.009569]  process_one_work+0x198/0x320
[    2.013579]  worker_thread+0x48/0x420
[    2.017252]  kthread+0xf0/0x120
[    2.020394]  ret_from_fork+0x10/0x18
[    2.023977] SMP: stopping secondary CPUs
[    2.027901] Kernel Offset: disabled
[    2.031391] CPU features: 0x0002,2100600c
[    2.035401] Memory Limit: none
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Fixes: 688f1dfb ("Input: keyboard - imx_sc: Add i.MX system controller key support")
Link: https://lore.kernel.org/r/1573730499-2224-1-git-send-email-Anson.Huang@nxp.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>