proc: proc_init_inodecache() can't fail

kmem_cache creation code will panic, don't return anything.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>

fs/proc/internal.h

@@ -66,7 +66,7 @@ extern const struct inode_operations proc_net_inode_operations;
 
 void free_proc_entry(struct proc_dir_entry *de);
 
-int proc_init_inodecache(void);
+void proc_init_inodecache(void);
 
 static inline struct pid *proc_pid(struct inode *inode)
 {