signal/riscv: Use force_sig_fault where appropriate

Filling in struct siginfo before calling force_sig_info a tedious and
error prone process, where once in a great while the wrong fields
are filled out, and siginfo has been inconsistently cleared.

Simplify this process by using the helper force_sig_fault.  Which
takes as a parameters all of the information it needs, ensures
all of the fiddly bits of filling in struct siginfo are done properly
and then calls force_sig_info.

In short about a 5 line reduction in code for every time force_sig_info
is called, which makes the calling function clearer.

Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Albert Ou <albert@sifive.com>
Cc: linux-riscv@lists.infradead.org
Acked-by: Palmer Dabbelt <palmer@sifive.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

arch/riscv/kernel/traps.c

@@ -66,14 +66,7 @@ void die(struct pt_regs *regs, const char *str)
 static inline void do_trap_siginfo(int signo, int code,
 	unsigned long addr, struct task_struct *tsk)
 {
-	siginfo_t info;
-
-	clear_siginfo(&info);
-	info.si_signo = signo;
-	info.si_errno = 0;
-	info.si_code = code;
-	info.si_addr = (void __user *)addr;
-	force_sig_info(signo, &info, tsk);
+	force_sig_fault(signo, code, (void __user *)addr, tsk);
 }
 
 void do_trap(struct pt_regs *regs, int signo, int code,