thunderbolt: Drop unnecessary read when writing LC command in Ice Lake

The read is not needed as we overwrite the returned value in the next
line anyway so drop it.

Fixes: 3cdb9446 ("thunderbolt: Add support for Intel Ice Lake")
Reported-by: Nicholas Johnson <nicholas.johnson-opensource@outlook.com.au>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>