linux-user/aarch64: Set siginfo_t addr field for SIGTRAP signals

linux-user/aarch64: Set siginfo_t addr field for SIGTRAP signals

When generating a TRAP_BRKPT SIGTRAP, set the siginfo_t addr field
to the PC where the breakpoint/singlestep trap occurred; this is
what the kernel does for this signal for this architecture.

Fixes: Coverity 1459154
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210813131809.28655-2-peter.maydell@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>