fix IPMI compile errors with PROC_FS=n

This patch fixes the following compile errors with CONFIG_PROC_FS=n:

<-- snip -->

...
CC [M] drivers/char/ipmi/ipmi_msghandler.o
drivers/char/ipmi/ipmi_msghandler.c:3301: proc_ipmi_root' undeclared here (not in a function) drivers/char/ipmi/ipmi_msghandler.c:3301: initializer element is not constant drivers/char/ipmi/ipmi_msghandler.c:3301: (near initialization for __ksymtab_proc_ipmi_root.value') drivers/char/ipmi/ipmi_msghandler.c:1535: warning: ipmb_file_read_proc' defined but not used drivers/char/ipmi/ipmi_msghandler.c:1551: warning: version_file_read_proc' defined but not used drivers/char/ipmi/ipmi_msghandler.c:1561: warning: `stat_file_read_proc' defined but not used
...
CC [M] drivers/char/ipmi/ipmi_poweroff.o
drivers/char/ipmi/ipmi_poweroff.c: In function `ipmi_poweroff_init':
drivers/char/ipmi/ipmi_poweroff.c:616: warning: implicit declaration of function unregister_sysctl_table' drivers/char/ipmi/ipmi_poweroff.c:616: ipmi_table_header' undeclared (first use in this function) drivers/char/ipmi/ipmi_poweroff.c:616: (Each undeclared identifier is reported only once drivers/char/ipmi/ipmi_poweroff.c:616: for each function it appears in.)

<-- snip -->

@@ -57,6 +57,7 @@
 
 #ifdef CONFIG_PROC_FS
 struct proc_dir_entry *proc_ipmi_root = NULL;
+EXPORT_SYMBOL(proc_ipmi_root);
 #endif /* CONFIG_PROC_FS */
 
 #define MAX_EVENTS_IN_QUEUE	25

@@ -3298,6 +3299,5 @@
 EXPORT_SYMBOL(ipmi_set_my_LUN);
 EXPORT_SYMBOL(ipmi_get_my_LUN);
 EXPORT_SYMBOL(ipmi_smi_add_proc_entry);
-EXPORT_SYMBOL(proc_ipmi_root);
 EXPORT_SYMBOL(ipmi_user_set_run_to_completion);
 EXPORT_SYMBOL(ipmi_free_recv_msg);

@@ -612,11 +612,14 @@
 #endif
 
 	rv = ipmi_smi_watcher_register(&smi_watcher);
+
+#ifdef CONFIG_PROC_FS
 	if (rv) {
 		unregister_sysctl_table(ipmi_table_header);
 		printk(KERN_ERR PFX "Unable to register SMI watcher: %d\n", rv);
 		goto out_err;
 	}
+#endif
 
  out_err:
 	return rv;