gdbstub: Allow specifying a reason in stop packets

gdbstub: Allow specifying a reason in stop packets

The upcoming syscall catchpoint support needs to send stop packets with
an associated reason to GDB. Add an extra parameter to gdb_handlesig()
for that, and rename it to gdb_handlesig_reason(). Provide a
compatibility wrapper with an old name.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Message-Id: <20240202152506.279476-3-iii@linux.ibm.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20240207163812.3231697-12-alex.bennee@linaro.org>