linux-user/sparc: Use force_sig_fault

Use the new function instead of setting up a target_siginfo_t
and calling queue_signal. Fill in the missing PC for SIGTRAP.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220107213243.212806-24-richard.henderson@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>