linux-user/mips: 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
and SIGFPE; use force_sig (SI_KERNEL) for EXCP_DSPDIS.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220107213243.212806-16-richard.henderson@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>