linux-user: Propagate siginfo_t through to handle_cpu_signal()

Currently all the architecture/OS specific cpu_signal_handler()
functions call handle_cpu_signal() without passing it the
siginfo_t. We're going to want that so we can look at the si_code
to determine whether this is a SEGV_ACCERR access violation or
some other kind of fault, so change the functions to pass through
the pointer to the siginfo_t rather than just the si_addr value.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <1511879725-9576-2-git-send-email-peter.maydell@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>