drm/amdgpu: skip disabling fence driver src_irqs when device is unplugged

drm/amdgpu: skip disabling fence driver src_irqs when device is unplugged

When performing device unbind or halt, we have disabled all irqs at the
very begining like amdgpu_pci_remove or amdgpu_device_halt. So
amdgpu_irq_put for irqs stored in fence driver should not be called
any more, otherwise, below calltrace will arrive.

[  139.114088] WARNING: CPU: 2 PID: 1550 at drivers/gpu/drm/amd/amdgpu/amdgpu_irq.c:616 amdgpu_irq_put+0xf6/0x110 [amdgpu]
[  139.114655] Call Trace:
[  139.114655]  <TASK>
[  139.114657]  amdgpu_fence_driver_hw_fini+0x93/0x130 [amdgpu]
[  139.114836]  amdgpu_device_fini_hw+0xb6/0x350 [amdgpu]
[  139.114955]  amdgpu_driver_unload_kms+0x51/0x70 [amdgpu]
[  139.115075]  amdgpu_pci_remove+0x63/0x160 [amdgpu]
[  139.115193]  ? __pm_runtime_resume+0x64/0x90
[  139.115195]  pci_device_remove+0x3a/0xb0
[  139.115197]  device_remove+0x43/0x70
[  139.115198]  device_release_driver_internal+0xbd/0x140

Signed-off-by: Guchun Chen <guchun.chen@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>