make tx/rx fifo size a param, also fix the empty dma problem by adjusting the state...

make tx/rx fifo size a param, also fix the empty dma problem by adjusting the state machine.

dev/ns_gige.cc:
    make tx/rx fifo sizes a param. the default is 128K for each.  also, make the state machine not move onto txFragRead if there is no room in the txfifo for data.
dev/ns_gige.hh:
    make tx/rx fifo size a param

--HG--
extra : convert_revision : ed91eb31c2b21d4cdc6de87d8641df6197be5209