accel/habanalabs: use device-name directory in debugfs-driver-habanalabs

The device debugfs directory was modified to be named as the parent
device name.
Update the description of 'mmu' and 'mmu_error' to use the new path.

Signed-off-by: Tomer Tayar <[e-mail]>
Reviewed-by: Ofir Bitton <[e-mail]>
Signed-off-by: Ofir Bitton <[e-mail]>

Documentation/ABI/testing/debugfs-driver-habanalabs

···
                 and virtual address. The user should write the ASID and VA into
                 the file and then read the file to get the result.
                 e.g. to display info about VA 0x1000 for ASID 1 you need to do:
-                echo "1 0x1000" > /sys/kernel/debug/accel/0/mmu
+                echo "1 0x1000" > /sys/kernel/debug/accel/<parent_device>/mmu
 
 What:           /sys/kernel/debug/accel/<parent_device>/mmu_error
 Date:           Mar 2021
···
 Description:    Check and display page fault or access violation mmu errors for
                 all MMUs specified in mmu_cap_mask.
                 e.g. to display error info for MMU hw cap bit 9, you need to do:
-                echo "0x200" > /sys/kernel/debug/accel/0/mmu_error
-                cat /sys/kernel/debug/accel/0/mmu_error
+                echo "0x200" > /sys/kernel/debug/accel/<parent_device>/mmu_error
+                cat /sys/kernel/debug/accel/<parent_device>/mmu_error
 
 What:           /sys/kernel/debug/accel/<parent_device>/monitor_dump
 Date:           Mar 2022