Hi Vincenzo,

I love your patch! Yet something to improve:

[auto build test ERROR on shawnguo/for-next]
[also build test ERROR on v5.6-rc4 next-20200306]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Vincenzo-Frascino/drivers-soc-Fix-COMPILE_TEST-for-IMX-SCU/20200307-033704
base:   https://git.kernel.org/pub/scm/linux/kernel/git/shawnguo/linux.git for-next
config: i386-randconfig-e003-20200305 (attached as .config)
compiler: gcc-7 (Debian 7.5.0-5) 7.5.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   ld: drivers/firmware/imx/imx-scu.o: in function `imx_scu_call_rpc':
>> imx-scu.c:(.text+0xbb): undefined reference to `mbox_send_message'
   ld: drivers/firmware/imx/imx-scu.o: in function `imx_scu_probe':
>> imx-scu.c:(.text+0x356): undefined reference to `mbox_request_channel_byname'
   ld: drivers/firmware/imx/imx-scu-irq.o: in function `imx_scu_enable_general_irq_channel':
>> imx-scu-irq.c:(.text+0x22b): undefined reference to `mbox_request_channel_byname'

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org