staging: ks7010: use linux circular buffer header macros to handle tx and rx queues

This commit replace current custom implementation of some circular
buffer head and tail logic in favour of the use of macros defined
in linux circ_buf.h header. Queue related inline function names
have been review also.

Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>