sim: rl78: drop obsolete manual dependency rules

We have GNU make generate these for us automatically now, so there's
no need to manually specify any deps.

sim/rl78/Makefile.in

@@ -34,18 +34,3 @@ SIM_OBJS = \
 	trace.o
 
 ## COMMON_POST_CONFIG_FRAG
-
-arch = rl78
-
-err.o : err.h
-fpu.o : cpu.h fpu.h
-gdb-if.o : cpu.h mem.h load.h \
-           $(srcdir)/../../include/sim/callback.h \
-	   $(srcdir)/../../include/sim/sim.h \
-	   $(srcdir)/../../include/gdb/signals.h \
-	   $(srcdir)/../../include/gdb/sim-rl78.h
-load.o : ../../bfd/bfd.h cpu.h mem.h
-main.o : ../../bfd/bfd.h cpu.h mem.h load.h
-mem.o : mem.h cpu.h
-reg.o : cpu.h
-rl78.o : $(srcdir)/../../include/opcode/rl78.h cpu.h mem.h