remove debug messages for tx dma testing (will be put again after tx
revision)
add wmb before posting write[q/l] for tx
add clflush right after wmb in lbuf_xmit

- originally, pcie read request invalidates its address range carrying
No Snoop bit cleared in its TLP header. But, I found that not invalidating
packets are rarely happending, thereby breaking consistency between
SW and HW. We haven't found the cause by now, but clflush right before
write[q/l] solves the issue as a explicit cache flush from sw-side.
fix error handling bug when phy chip initialization fails
Merge branch 'master' into tx_batching
replace wmb->clflush with safe flush (mb->clflush->mb)
Merge branch 'tx_batching' of https://github.com/NetFPGA-NewNIC/linux-driver into tx_batching