staging: et131x: improve code consistency: access struct tx_ring
staging: et131x: improve code consistency: access struct tx_ring

Let all the code use a pointer called tx_ring to access struct tx_ring
members.

Signed-off-by: ZHAO Gang <afc9accd6d61593e24a7fa4c4294166f24b95ffb@gmail.com>
Acked-by: Mark Einon <78d8af80769b0cbc00e314928418dc93597f13ae@gmail.com>
Signed-off-by: Greg Kroah-Hartman <4645f7897fd33786a2ee1264d590b3c400559d85@linuxfoundation.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs