powerpc/prom_init: Pass the "os-term" message to hypervisor

The "os-term" RTAS calls has one argument with a message address of OS
termination cause. rtas_os_term() already passes it but the recently
added prom_init's version of that missed it; it also does not fill
args correctly.

This passes the message address and initializes the number of arguments.

Fixes: 6a9c930b ("powerpc/prom_init: Add the ESM call to prom_init")
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200312074404.87293-1-aik@ozlabs.ru

arch/powerpc/kernel/prom_init.c

@@ -1773,6 +1773,9 @@ static void __init prom_rtas_os_term(char *str)
 	if (token == 0)
 		prom_panic("Could not get token for ibm,os-term\n");
 	os_term_args.token = cpu_to_be32(token);
+	os_term_args.nargs = cpu_to_be32(1);
+	os_term_args.nret = cpu_to_be32(1);
+	os_term_args.args[0] = cpu_to_be32(__pa(str));
 	prom_rtas_hcall((uint64_t)&os_term_args);
 }
 #endif /* CONFIG_PPC_SVM */