target/arm: Remove antique TODO comment

Remove a TODO comment about implementing the vectored interrupt
controller. We have had an implementation of that for a decade;
it's in hw/intc/pl190.c.
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: NRichard Henderson <richard.henderson@linaro.org>
Message-id: 20181106164118.16184-1-peter.maydell@linaro.org
Reviewed-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: NAlex Bennée <alex.bennee@linaro.org>

target/arm/helper.c

@@ -8378,7 +8378,6 @@ static void arm_cpu_do_interrupt_aarch32(CPUState *cs)
         return;
     }
 
-    /* TODO: Vectored interrupt controller.  */
     switch (cs->exception_index) {
     case EXCP_UDEF:
         new_mode = ARM_CPU_MODE_UND;