media: qcom: camss: fix error path on configuration of power domains

media: qcom: camss: fix error path on configuration of power domains

There is a chance to meet runtime issues during configuration of CAMSS
power domains, because on the error path dev_pm_domain_detach() is
unexpectedly called with NULL or error pointer.

One of the simplest ways to reproduce the problem is to probe CAMSS
driver before registration of CAMSS power domains, for instance if
a platform CAMCC driver is simply not built.

Warning backtrace example:

    Unable to handle kernel NULL pointer dereference at virtual address 00000000000001a2

    <snip>

    pc : dev_pm_domain_detach+0x8/0x48
    lr : camss_probe+0x374/0x9c0

    <snip>

    Call trace:
     dev_pm_domain_detach+0x8/0x48
     platform_probe+0x70/0xf0
     really_probe+0xc4/0x2a8
     __driver_probe_device+0x80/0x140
     driver_probe_device+0x48/0x170
     __device_attach_driver+0xc0/0x148
     bus_for_each_drv+0x88/0xf0
     __device_attach+0xb0/0x1c0
     device_initial_probe+0x1c/0x30
     bus_probe_device+0xb4/0xc0
     deferred_probe_work_func+0x90/0xd0
     process_one_work+0x164/0x3e0
     worker_thread+0x310/0x420
     kthread+0x120/0x130
     ret_from_fork+0x10/0x20

Fixes: 23aa4f0cd327 ("media: qcom: camss: Move VFE power-domain specifics into vfe.c")
Cc: <stable@vger.kernel.org>
Signed-off-by: Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org>
Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>