ath5k: Use common crypt capabilities flags

Replace ah_aes_support and ah_combined_mic with common ath_crypt_caps
ATH_CRYPT_CAP_CIPHER_AESCCM and ATH_CRYPT_CAP_MIC_COMBINED.

Signed-off-by: Bruno Randolf <br1@einfach.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>