target/arm/translate.c: Fix missing 'break' for TT insns

The code where we added the TT instruction was accidentally
missing a 'break', which meant that after generating the code
to execute the TT we would fall through to 'goto illegal_op'
and generate code to take an UNDEF insn.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20180206103941.13985-1-peter.maydell@linaro.org

target/arm/translate.c

@@ -9925,6 +9925,7 @@ static void disas_thumb2_insn(DisasContext *s, uint32_t insn)
                         tcg_temp_free_i32(addr);
                         tcg_temp_free_i32(op);
                         store_reg(s, rd, ttresp);
+                        break;
                     }
                     goto illegal_op;
                 }