Update deprecated/unused Chisel APIs

These have been deprecated since Chisel 3.6.0. They are being removed in
Chisel 6, and will become compile errors at that point.

fpga/src/main/scala/arty100t/HarnessBinders.scala

@@ -1,7 +1,6 @@
 package chipyard.fpga.arty100t
 
 import chisel3._
-import chisel3.experimental.{DataMirror, Direction}
 
 import freechips.rocketchip.jtag.{JTAGIO}
 import freechips.rocketchip.subsystem.{PeripheryBusKey}

fpga/src/main/scala/vcu118/bringup/IOBinders.scala

@@ -1,7 +1,7 @@
 package chipyard.fpga.vcu118.bringup
 
 import chisel3._
-import chisel3.experimental.{IO, DataMirror}
+import chisel3.reflect.DataMirror
 
 import freechips.rocketchip.util.{HeterogeneousBag}
 import freechips.rocketchip.tilelink.{TLBundle}