sparc64: make string buffers large enough

My static checker complains that if "lvl" is ULONG_MAX (this is 64 bit)
then some of the strings will overflow.  I don't know if that's possible
but it seems simple enough to make the buffers slightly larger.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>