sh_eth: fix typo in comment to BCULR write

Simon has noticed a typo in the comment accompaining the BCULR write --
fix it and move the comment before the write (following the style of
the other comments), while at it...

Reported-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>