iwl3945: Change crypto parameter name

Now that we're using iwl_mod_params, we want our module parameters names to be
in sync with the structure.
So, to set iwl_mod_params.sw_crypto, we'd better use a "swcrypto" parameter
name instead of the "hwcrypto" current one.
Moreover, by setting the decrypted flag properly, this patch also fixes the HW
crypto path for 3945 (the current code is not setting it when running HW
crypto).

This is a bug fix for bug #1872
( http://www.intellinuxwireless.org/bugzilla/show_bug.cgi?id=1872

 )

Signed-off-by: Samuel Ortiz <samuel.ortiz@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>