riscv: no __user for probe_kernel_address()

In is_valid_bugaddr(), probe_kernel_address() is called with
the PC casted to (bug_inst_t __user *) but this function
only take a plain void* as argument, not a __user pointer.

Fix this by removing the unnneded __user in the cast.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>

arch/riscv/kernel/traps.c

@@ -160,7 +160,7 @@ int is_valid_bugaddr(unsigned long pc)
 
 	if (pc < PAGE_OFFSET)
 		return 0;
-	if (probe_kernel_address((bug_insn_t __user *)pc, insn))
+	if (probe_kernel_address((bug_insn_t *)pc, insn))
 		return 0;
 	return (insn == __BUG_INSN);
 }