Getting a backtrace from the two occurrences, I see one added from:

   (debugfs_create_dir) from [<c04633f8>] (create_regulator+0xe0/0x220)
   (create_regulator) from [<c04681d8>] (_regulator_get+0x168/0x204)
   (_regulator_get) from [<c04682e0>] (regulator_bulk_get+0x64/0xf4)
   (regulator_bulk_get) from [<c04696f0>] 
(devm_regulator_bulk_get+0x40/0x74)
   (devm_regulator_bulk_get) from [<bf00af44>] 
(panfrost_device_init+0x1b4/0x48c [panfrost])
   (panfrost_device_init [panfrost]) from [<bf00a4d4>] 
(panfrost_probe+0x94/0x184 [panfrost])
   (panfrost_probe [panfrost]) from [<c04ee694>] 
(platform_drv_probe+0x48/0x94)

And the other:

   (debugfs_create_dir) from [<c04633f8>] (create_regulator+0xe0/0x220)
   (create_regulator) from [<c04681d8>] (_regulator_get+0x168/0x204)
   (_regulator_get) from [<c05c1280>] (dev_pm_opp_set_regulators+0x6c/0x184)
   (dev_pm_opp_set_regulators) from [<bf00b4ac>] 
(panfrost_devfreq_init+0x38/0x1ac [panfrost])
   (panfrost_devfreq_init [panfrost]) from [<bf00a508>] 
(panfrost_probe+0xc8/0x184 [panfrost])
   (panfrost_probe [panfrost]) from [<c04ee694>] 
(platform_drv_probe+0x48/0x94)