iio: light: isl29028: Fix the warning in isl29028_remove()

The driver use the non-managed form of the register function in
isl29028_remove(). To keep the release order as mirroring the ordering
in probe, the driver should use non-managed form in probe, too.

The following log reveals it:

[   32.374955] isl29028 0-0010: remove
[   32.376861] general protection fault, probably for non-canonical address 0xdffffc0000000006: 0000 [#1] PREEMPT SMP KASAN PTI
[   32.377676] KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]
[   32.379432] RIP: 0010:kernfs_find_and_get_ns+0x28/0xe0
[   32.385461] Call Trace:
[   32.385807]  sysfs_unmerge_group+0x59/0x110
[   32.386110]  dpm_sysfs_remove+0x58/0xc0
[   32.386391]  device_del+0x296/0xe50
[   32.386959]  cdev_device_del+0x1d/0xd0
[   32.387231]  devm_iio_device_unreg+0x27/0xb0
[   32.387542]  devres_release_group+0x319/0x3d0
[   32.388162]  i2c_device_remove+0x93/0x1f0

Fixes: 2db5054a

 ("staging: iio: isl29028: add runtime power management support")
Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
Link: https://lore.kernel.org/r/20220717004241.2281028-1-zheyuma97@gmail.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>