ice: fix memory corruption bug with suspend and rebuild

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

ice: fix memory corruption bug with suspend and rebuild

The ice driver would previously panic after suspend. This is caused
from the driver only calling the ice_vsi_free_q_vectors() function by
itself, when it is suspending. Since commit b3e7b3a6ee92 ("ice: prevent
NULL pointer deref during reload") the driver has zeroed out
num_q_vectors, and only restored it in ice_vsi_cfg_def().

This further causes the ice_rebuild() function to allocate a zero length
buffer, after which num_q_vectors is updated, and then the new value of
num_q_vectors is used to index into the zero length buffer, which
corrupts memory.

The fix entails making sure all the code referencing num_q_vectors only
does so after it has been reset via ice_vsi_cfg_def().

I didn't perform a full bisect, but I was able to test against 6.1.77
kernel and that ice driver works fine for suspend/resume with no panic,
so sometime since then, this problem was introduced.

Also clean up an un-needed init of a local variable in the function
being modified.

PANIC from 6.8.0-rc1:

[1026674.915596] PM: suspend exit
[1026675.664697] ice 0000:17:00.1: PTP reset successful
[1026675.664707] ice 0000:17:00.1: 2755 msecs passed between update to cached PHC time
[1026675.667660] ice 0000:b1:00.0: PTP reset successful
[1026675.675944] ice 0000:b1:00.0: 2832 msecs passed between update to cached PHC time
[1026677.137733] ixgbe 0000:31:00.0 ens787: NIC Link is Up 1…