Definition of workqueue and semaphore as static

Signed-off-by: Christina Quast <chrysh.ng+github@gmail.com>
Moved sync message to earlier moment in time

Sync took place on first call to transmit_message(), which could have introduced race conditions because the message structures where already initialised for sending the packet passed from the userspace to the board controller and we had a recursive call to perform_transaction().
Now the syncing takes place on the first call of transmit_packet from higher level kernel modules.

Signed-off-by: Christina Quast <chrysh.ng+github@gmail.com>
Removed current and temporary packet pointer

Passing pointer to packet to be send as function parameters now.
This is only possible because sending the initial sync message to the board controller moved to an earlier moment.

Signed-off-by: Christina Quast <chrysh.ng+github@gmail.com>
Temporary buffer changed from static to local variable

The buffer was only used in one function transmitting messages

Signed-off-by: Christina Quast <chrysh.ng+github@gmail.com>
Curr pkt pointer converted from static to local variable

Signed-off-by: Christina Quast <chrysh.ng+github@gmail.com>
Removed redundant static pointer to struct tty

We already have this pointer in our central struct bcc_struct

Signed-off-by: Christina Quast <chrysh.ng+github@gmail.com>
Removed second argument from transmit_packet()

Highlevel kernel modules using the interface to drbcc-core should not be capable to control which response message they want to get back from the board controller.

Signed-off-by: Christina Quast <chrysh.ng+github@gmail.com>