wifi: iwlwifi: pcie: clear FW debug memory on init

When we restart the firmware, we shouldn't keep old debug data
around. Since the "allocate" function might not reallocate the
memory block (it's only freed when we unbind from the device),
clear the memory to have a clean slate for debug data.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230613155501.73c32255a132.Ibd7101dcd285b01ee879fddfbf52c30d49ced3c0@changeid


Signed-off-by: Johannes Berg <johannes.berg@intel.com>