clk: microchip: fix potential UAF in auxdev release callback

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

clk: microchip: fix potential UAF in auxdev release callback

Similar to commit 1c11289b34ab ("peci: cpu: Fix use-after-free in

adev_release()"), the auxiliary device is not torn down in the correct

order. If auxiliary_device_add() fails, the release callback will be

called twice, resulting in a UAF. Due to timing, the auxdev code in this

driver "took inspiration" from the aforementioned commit, and thus its

bugs too!

Moving auxiliary_device_uninit() to the unregister callback instead

avoids the issue.