Fix for v850e divq instruction

This is the last of the correctness fixes I've been carrying around for the
v850.

Like the other recent fixes, this is another case where we haven't been as
careful as we should WRT host vs target types.   For the divq instruction
both operands are 32 bit types.  Yet in the simulator code we convert them
from unsigned int to signed long by assignment.  So 0xfffffffb (aka -5)
turns into 4294967291 and naturally that changes the result of our division.

The fix is simple, insert a cast to int32_t to force interpretation as a
signed value.

Testcase for the simulator is included.  It has a trivial dependency on the
bins patch.

sim/testsuite/v850/divq.cgs

@@ -0,0 +1,11 @@
+# v850 bins
+# mach: v850e3v5
+# as: -mv850e3v5
+
+	.include "testutils.inc"
+	seti	0xfffffffb r11
+	seti	0x32 r10
+	divq	r11, r10, r11
+	reg	r10, 0xfffffff6
+	reg	r11, 0x0
+	pass

sim/v850/simops.c

@@ -3135,8 +3135,8 @@ v850_div (SIM_DESC sd, unsigned int op0, unsigned int op1, unsigned int *op2p, u
   bfd_boolean     overflow = FALSE;
   
   /* Compute the result.  */
-  divide_by   = op0;
-  divide_this = op1;
+  divide_by   = (int32_t)op0;
+  divide_this = (int32_t)op1;
 
   if (divide_by == 0 || (divide_by == -1 && divide_this == (1 << 31)))
     {