drm/amdgpu: Fix runtime PM leak in amdgpu_debugfs_test_ib_show()
In the Linux kernel, the following vulnerability has been resolved:
drm/amdgpu: Fix runtime PM leak in amdgpu_debugfs_test_ib_show()
amdgpu_debugfs_test_ib_show() resumes the device with
pm_runtime_get_sync() before taking the reset domain semaphore with
down_write_killable(). If the write lock acquisition is interrupted,
the function returns without calling pm_runtime_put_autosuspend(),
leaking the runtime PM reference acquired for the device and keeping
the GPU awake.
Drop the runtime PM reference on the interrupted down_write_killable()
error path before returning.
(cherry picked from commit ec30a576c2d4c0364549e6c04218f50704ef56c8)
