ath6kl: remove Bluetooth PAL code and WMI ACL TX/RX data support

ath6kl used to have an internal PAL for Bluetooth 3.0 support
but this is no longer supported. The target used a WMI with an
ACL header for supporting these frames. Userspace would use
the ioctl AR6000_XIOCTL_ACL_DATA to send data to the target
and the firmware would generate ACL frames.

Remove both the parsing of the frames and the ioctl support.
We leave a warning for now for if the target generates some
sort of ACL data frame, later on we can remove this warning
once we have proven the target is no longer generating these
frames. It should be noted this also provides a fix for the
processing of spurious ACL data frames from the target,
previously they would not be dropped if they were generated
by the target but EXPORT_HCI_PAL_INTERFACE was not compiled
in.

Cc: Naveen Singh <nsingh@atheros.com>
Cc: Prerepa (Dham) Viswanadham <dham@atheros.com>
Cc: Shanmugamkamatchi Balashanmugam <sbalashanmugam@atheros.com>
Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>