sim: lm32/m32r: drop redundant opcode/cgen.h include

The xxx-desc.h header file already includes this, and it's how the
other cgen ports are getting it, so drop it from these two.
diff --git a/sim/lm32/sim-main.h b/sim/lm32/sim-main.h
index 0e13aeb..ce30349 100644
--- a/sim/lm32/sim-main.h
+++ b/sim/lm32/sim-main.h
@@ -32,7 +32,6 @@
 #include "sim-base.h"
 #include "cgen-sim.h"
 #include "lm32-sim.h"
-#include "opcode/cgen.h"
 
 struct lm32_sim_cpu
 {
diff --git a/sim/m32r/sim-main.h b/sim/m32r/sim-main.h
index a5a745d..7096232 100644
--- a/sim/m32r/sim-main.h
+++ b/sim/m32r/sim-main.h
@@ -15,7 +15,6 @@
 #include "sim-base.h"
 #include "cgen-sim.h"
 #include "m32r-sim.h"
-#include "opcode/cgen.h"
 
 struct m32r_sim_cpu {
   M32R_MISC_PROFILE m32r_misc_profile;