There is only one clock board, so use -1 as the 'id' so we get just
the base name as the LED device name string.

There are multiple FHC boards potentially in a system so use the board
number as the 'id' value for that case.
Reported-by: Meelis Roos <mroos@linux.ee>
Tested-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: David S. Miller <davem@davemloft.net>