Ath6kl: Completed ath6kl_configure_target.

* Add ath6kl_set_htc_params;
Ath6kl: upload board file for ar6004.

* Add two BMI function:
    o ath6kl_bmi_reg_write
    o ath6kl_bmi_reg_read
* Change the signature of ath6kl_bmi_write buf argument from 'uint8_t *'
to 'const uint8_t *'. This is more correct and also because firmware(9)
points to a const qualified area;
* Add ath6kl_upload_board_file;
* Add partially ath6kl_init_upload, which is called from ath6kl_init_hw_params;