iwlwifi: pcie: free IML DMA memory allocation

In the case of gen3 devices with image loader (IML) support,
we were leaking the IML DMA allocation and never freeing it.
Fix that.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20210618105614.07e117dbedb7.I7bb9ebbe0617656986c2a598ea5e827b533bd3b9@changeid


Signed-off-by: Luca Coelho <luciano.coelho@intel.com>