CVE-2026-74629: net/dibs: Correct freeing of dmb_clientid_arr

In the Linux kernel, the following vulnerability has been resolved:

net/dibs: Correct freeing of dmbclientidarr

A dibs device interrupt handler can be active after dibsdevdel() and may still access dmbclientidarr. (UAF)

In case of a failure in dibsdevadd() being called by dibslodevprobe() dmbclientidarr is freed twice (double free).

Free dmbclientidarr in dibsdevrelease() after last reference is gone. Note that allocating in dibsdevadd() instead of dibsdevalloc() is ok for now, because no dmbs can be registered before dibsdevadd().