The driver only exposed a CAM SIM. Userland had no way to reach the
device for anything that is not a SCSI command, so reading a descriptor
or an attribute was impossible.
Add /dev/ufshci%d as a root only node and the ioctl ABI header for it.
The node answers no ioctl yet. The header pulls in ufshci.h, which
declares bool only under _KERNEL, so include stdbool.h for userland the
way nvme.h already does.
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