This commit adds port parameters to Kconfig, using the same
values we currently have in wrsw_hal.conf (i.e: tx delay = 0,
rx delay = 160000 or 161200).

These values are used in later commits, where this dot-config
stuff is replacing wrsw_hal.conf.  The "role=" and "fiber=" values
will be used later, but I'd better write them now to avoid
excessive edits to this file.
Signed-off-by: Alessandro Rubini <rubini@gnudd.com>