Staging: b3dfg: fixups and improvements

- Added support for cable plug/unplug detection.
 - Improvements to error handling.
 - Switch to the pci_* DMA API.
 - Removed set_num_buffers functionality.
 - Locking review.
 - Unconditionally disable transmission when releasing device.

Signed-off-by: Justin Bronder <jsbronder@brontes3d.com>
Cc: Duane Griffin <duaneg@dghda.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>