ath6kl: AR6004 3.0 support.
This patch adds support for AR6004 v3.0 hardware.

Signed-off-by: Ram Ranganathan <rrangana@qca.qualcomm.com>
ath6kl: Disable credit scheme for HSIC.

AR6004 2.0 and later has USB DMA issue, so it should no longer need
the credit scheme. Disabling it by default.

Signed-off-by: Ram Ranganathan <rrangana@qca.qualcomm.com>
ath6kl: Enable device tree support for AR6004 over HSIC.

This patch enables device tree support for AR6004 over HSIC
interface.
Signed-off-by: Ram Ranganathan <rrangana@qca.qualcomm.com>