powerpc: Fix error return in rtas_flash module init

module_init should return 0 or a negative errno.

Signed-off-by: Anton Blanchard <[e-mail]>
Signed-off-by: Benjamin Herrenschmidt <[e-mail]>

arch/powerpc/kernel/rtas_flash.c

···
 	if (rtas_token("ibm,update-flash-64-and-reboot") ==
 		       RTAS_UNKNOWN_SERVICE) {
 		pr_info("rtas_flash: no firmware flash support\n");
-		return 1;
+		return -EINVAL;
 	}
 
 	rtas_validate_flash_data.buf = kzalloc(VALIDATE_BUF_SIZE, GFP_KERNEL);