qcacld-3.0: Fix incorrect size issue __lim_get_sme_join_req_size_for_alloc

__lim_get_sme_join_req_size_for_alloc returning 2 byte extra length,
using this incorrect buffer size to copy buffer may cause buffer
overflow.

Fix the same by returning correct size.

Change-Id: If9a5f3546955c72f54a11fedec76f24cd122319a
CRs-Fixed: 2034215

core/mac/src/pe/lim/lim_process_sme_req_messages.c

@@ -465,7 +465,7 @@ static uint16_t __lim_get_sme_join_req_size_for_alloc(uint8_t *pBuf)
 
 	pBuf += sizeof(uint16_t);
 	len = lim_get_u16(pBuf);
-	return len + sizeof(uint16_t);
+	return len;
 }
 
 /**