staging: rtl8192e: Use kmemdup for duplicating memory

Instead of allocating memory (kmalloc) and copying (memcpy)
from source, memory can be duplicated using kmemdup
Signed-off-by: Hema Prathaban <hemaklnce@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8192e/rtllib_softmac.c

@@ -1801,10 +1801,9 @@ static inline u16 auth_parse(struct sk_buff *skb, u8** challenge, int *chlen)
 
 		if (*(t++) == MFIE_TYPE_CHALLENGE) {
 			*chlen = *(t++);
-			*challenge = kmalloc(*chlen, GFP_ATOMIC);
+			*challenge = kmemdup(t, *chlen, GFP_ATOMIC);
 			if (!*challenge)
 				return -ENOMEM;
-			memcpy(*challenge, t, *chlen);
 		}
 	}
 	return cpu_to_le16(a->status);