fix(drivers/marvell/comphy-3700): fix comments about selector register values

The comments about selector register values are wrong.

Bit 0 configures only lane 1, bit 4 only lane 0, and bit 8 lanes 0 and
2.

Signed-off-by: Marek Behún <marek.behun@nic.cz>
Change-Id: Iffe42374f92654ebe570557e0d462204439cfa31
1 file changed