sim: delete duplicate SIGINT handling

Many of the simulators change the SIGINT handler.
E.g., moxie/interp.c:

  sigsave = signal (SIGINT, interrupt);

However, this is unnecessary.
remote-sim.h already provides an API for asynchronously stopping
a sim; and both gdb and the drivers (run.c and nrun.c at least,
I didn't check the others) install a SIGINT handler which
calls this method.

URL: https://sourceware.org/bugzilla/show_bug.cgi?id=16450
Reported-by: Tom Tromey <tromey@redhat.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

sim/mcore/interp.c

@@ -472,12 +472,6 @@ set_initial_gprs ()
   cpu.gr[PARM4] = cpu.gr[0];
 }
 
-static void
-interrupt ()
-{
-  cpu.asregs.exception = SIGINT;
-}
-
 /* Functions so that trapped open/close don't interfere with the
    parent's functions.  We say that we can't close the descriptors
    that we didn't open.  exit() and cleanup() get in trouble here,
@@ -762,7 +756,6 @@ sim_resume (sd, step, siggnal)
   word ibuf;
   word pc;
   unsigned short inst;
-  void (* sigsave)();
   int memops;
   int bonus_cycles;
   int insts;
@@ -770,7 +763,6 @@ sim_resume (sd, step, siggnal)
   int cycs;
   word WLhash;
 
-  sigsave = signal (SIGINT, interrupt);
   cpu.asregs.exception = step ? SIGTRAP: 0;
   pc = cpu.asregs.pc;
 
@@ -1709,8 +1701,6 @@ sim_resume (sd, step, siggnal)
   cpu.asregs.cycles += insts;		/* and each takes a cycle */
   cpu.asregs.cycles += bonus_cycles;	/* and extra cycles for branches */
   cpu.asregs.cycles += memops * memcycles;	/* and memop cycle delays */
-  
-  signal (SIGINT, sigsave);
 }