hw/rtc/pl031: Send RTC_CHANGE QMP event

hw/rtc/pl031: Send RTC_CHANGE QMP event

The PL031 currently is not able to report guest RTC change to the QMP
monitor as opposed to mc146818 or spapr RTCs. This patch adds the call
to qapi_event_send_rtc_change() when the Load Register is written. The
value which is reported corresponds to the difference between the guest
reference time and the reference time kept in softmmu/rtc.c.

For instance adding 20s to the guest RTC value will report 20. Adding
an extra 20s to the guest RTC value will report 20 + 20 = 40.

The inclusion of qapi/qapi-types-misc-target.h in hw/rtl/pl031.c
require to compile the PL031 with specific_ss.add() to avoid
./qapi/qapi-types-misc-target.h:18:13: error: attempt to use poisoned
"TARGET_<ARCH>".

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20210920122535.269988-1-eric.auger@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>