Chisel3: bulk connect is not commutative

We haven't decided if this is a FIRRTL limitation that we should relax,
or a backwards incompatibility we're forced to live with.  Should make
for lively debate.

rocket/src/main/scala/rocket.scala

@@ -370,7 +370,7 @@ class Rocket extends CoreModule
   csr.io.exception := wb_reg_xcpt
   csr.io.cause := wb_reg_cause
   csr.io.retire := wb_valid
-  csr.io.host <> io.host
+  io.host <> csr.io.host
   io.fpu.fcsr_rm := csr.io.fcsr_rm
   csr.io.fcsr_flags := io.fpu.fcsr_flags
   csr.io.rocc <> io.rocc