Revert "drm/panthor: Fix undefined panthor_device_suspend/resume symbol issue"

This reverts commit 674dc7f61aefea81901c21402946074927e63f1a.

The commit causes a recursive dependency in kconfig:

drivers/iommu/Kconfig:14:error: recursive dependency detected!
drivers/iommu/Kconfig:14: symbol IOMMU_SUPPORT is selected by DRM_PANTHOR
drivers/gpu/drm/panthor/Kconfig:3: symbol DRM_PANTHOR depends on PM
kernel/power/Kconfig:183: symbol PM is selected by PM_SLEEP
kernel/power/Kconfig:117: symbol PM_SLEEP depends on HIBERNATE_CALLBACKS
kernel/power/Kconfig:35: symbol HIBERNATE_CALLBACKS is selected by XEN_SAVE_RESTORE
arch/x86/xen/Kconfig:67: symbol XEN_SAVE_RESTORE depends on XEN
arch/x86/xen/Kconfig:6: symbol XEN depends on PARAVIRT
arch/x86/Kconfig:781: symbol PARAVIRT is selected by HYPERV
drivers/hv/Kconfig:5: symbol HYPERV depends on X86_LOCAL_APIC
arch/x86/Kconfig:1106: symbol X86_LOCAL_APIC depends on X86_UP_APIC
arch/x86/Kconfig:1081: symbol X86_UP_APIC prompt is visible depending on PCI_MSI
drivers/pci/Kconfig:39: symbol PCI_MSI is selected by AMD_IOMMU
drivers/iommu/amd/Kconfig:3: symbol AMD_IOMMU depends on IOMMU_SUPPORT
For a resolution refer to Documentation/kbuild/kconfig-language.rst
subsection "Kconfig recursive dependency limitations"

Fixes: 674dc7f61aef ("drm/panthor: Fix undefined panthor_device_suspend/resume symbol issue")
Cc: Boris Brezillon <[e-mail]>
Cc: Liviu Dudau <[e-mail]>
Cc: Steven Price <[e-mail]>
Acked-by: Boris Brezillon <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]
Signed-off-by: Jani Nikula <[e-mail]>

drivers/gpu/drm/panthor/Kconfig

···
 	depends on ARM || ARM64 || COMPILE_TEST
 	depends on !GENERIC_ATOMIC64  # for IOMMU_IO_PGTABLE_LPAE
 	depends on MMU
-	depends on PM
 	select DEVFREQ_GOV_SIMPLE_ONDEMAND
 	select DRM_EXEC
 	select DRM_GEM_SHMEM_HELPER

drivers/gpu/drm/panthor/panthor_device.c

···
 	return 0;
 }
 
+#ifdef CONFIG_PM
 int panthor_device_resume(struct device *dev)
 {
 	struct panthor_device *ptdev = dev_get_drvdata(dev);
···
 	mutex_unlock(&ptdev->pm.mmio_lock);
 	return ret;
 }
+#endif