According to the aircrack-ng.org website you need to pass pass the arguments to /etc/modprobe.d/options file.
For 4965 card is says run
For 5100 card I would assume run
# echo options iwlagn swcrypto=1 >> /etc/modprobe.d/options
Then reboot. I can't confirm that this works as I don't have an Intel 4965 card or 5XXX card to test.
# echo options iwlagn swcrypto50=1 >> /etc/modprobe.d/options
Alternatively, if you just wanted to check to see if it works without making changes to the options file you could load and unload your driver.
# modprobe -r iwlagn
# modprobe iwlagn swcrypto50=1