usb: eth: r8152_fw: fix indentation

Apparently the indentation is wrong here, fix this to avoid compiler
warnings and puzzled readers.

Pointed out by GCC 6.2's -Wmisleading-indentation warning.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Marek Vasut <marex@denx.de>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>