[PATCH] mailbox: imx: Mark PM functions as __maybe_unused

[Aisheng Dong]

> From: Nathan Chancellor <natechancellor at gmail.com>
> Sent: Tuesday, June 23, 2020 9:04 AM
> 
> When CONFIG_PM and CONFIG_PM_SLEEP are unset, the following warnings
> occur:
> 
> drivers/mailbox/imx-mailbox.c:638:12: warning: 'imx_mu_runtime_resume'
> defined but not used [-Wunused-function]
>   638 | static int imx_mu_runtime_resume(struct device *dev)
>       |            ^~~~~~~~~~~~~~~~~~~~~
> drivers/mailbox/imx-mailbox.c:629:12: warning: 'imx_mu_runtime_suspend'
> defined but not used [-Wunused-function]
>   629 | static int imx_mu_runtime_suspend(struct device *dev)
>       |            ^~~~~~~~~~~~~~~~~~~~~~
> drivers/mailbox/imx-mailbox.c:611:12: warning: 'imx_mu_resume_noirq'
> defined but not used [-Wunused-function]
>   611 | static int imx_mu_resume_noirq(struct device *dev)
>       |            ^~~~~~~~~~~~~~~~~~~
> drivers/mailbox/imx-mailbox.c:601:12: warning: 'imx_mu_suspend_noirq'
> defined but not used [-Wunused-function]
>   601 | static int imx_mu_suspend_noirq(struct device *dev)
>       |            ^~~~~~~~~~~~~~~~~~~~
> 
> Mark these functions as __maybe_unused, which is the standard procedure for
> PM functions.
> 
> Fixes: bb2b2624dbe2 ("mailbox: imx: Add runtime PM callback to handle MU
> clocks")
> Signed-off-by: Nathan Chancellor <natechancellor at gmail.com>

Thanks for catching this.

Reviewed-by: Dong Aisheng <aisheng.dong at nxp.com>

Regards
Aisheng