net: ethernet: myricom: myri10ge: myri10ge.c: Cleaning up missing null-terminate after strncpy call

Added a guaranteed null-terminate after call to strncpy.

Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
Signed-off-by: David S. Miller <davem@davemloft.net>