qtnfmac: drop QTN_TLV_ID_NUM_IFACE_COMB TLV type

Information about interface combinations is now available in a fixed
portion of struct qlink_resp_get_mac_info. Use that information to
get interface combinations. TLV type QTN_TLV_ID_NUM_IFACE_COMB is
not needed anymore and can be dropped.

Signed-off-by: Igor Mitsyanko <igor.mitsyanko.os@quantenna.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>