Revert "arc: Determine a branch target of DBNZ correctly"

This reverts commit 8fa4b97.

Author: kolerov

gdb/arc-tdep.c

@@ -465,16 +465,6 @@ arc_insn_get_branch_target (const struct arc_instruction &insn)
 	 instruction, hence last two bits should be truncated.  */
       return pcrel_addr + align_down (insn.address, 4);
     }
-  /* DBNZ is the only branch instruction that keeps a branch address in
-     the second operand. It must be intercepted and treated differently. */
-  else if (insn.insn_class == DBNZ)
-    {
-      CORE_ADDR pcrel_addr = arc_insn_get_operand_value_signed (insn, 1);
-
-      /* Offset is relative to the 4-byte aligned address of the current
-	 instruction, hence last two bits should be truncated. */
-      return pcrel_addr + align_down (insn.address, 4);
-    }
   /* B, Bcc, BL, BLcc, LP, LPcc: PC = currentPC + operand.  */
   else if (insn.insn_class == BRANCH || insn.insn_class == LOOP)
     {