NetworkPkg/TlsDxe: clean up byte order conversion for EfiTlsCipherList

Fix the following style issues:

- "Data" is accessed through a pointer to UINT16 rather than to a pointer
  to EFI_TLS_CIPHER. While technically correct, UINT16 is harder to
  interpret against the UEFI spec.

- Array subscripting is written with weird *(Pointer + Offset)
  expressions, rather than with Pointer[Offset].

- The byte order is converted with HTONS(), while it should be NTOHS().
  Either way, use the Data1 and Data2 fields of EFI_TLS_CIPHER instead.

Cc: Jiaxin Wu <jiaxin.wu@intel.com>
Cc: Siyuan Fu <siyuan.fu@intel.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=915
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Fu Siyuan <siyuan.fu@intel.com>
Reviewed-by: Long Qin <qin.long@intel.com>
Reviewed-by: Jiaxin Wu <jiaxin.wu@intel.com>

NetworkPkg/TlsDxe/TlsProtocol.c

@@ -60,6 +60,7 @@ TlsSetSessionData (
   EFI_STATUS                Status;
   TLS_INSTANCE              *Instance;
   UINT16                    *CipherId;
+  CONST EFI_TLS_CIPHER      *TlsCipherList;
   UINTN                     CipherCount;
   UINTN                     Index;
 
@@ -113,9 +114,11 @@ TlsSetSessionData (
       goto ON_EXIT;
     }
 
+    TlsCipherList = (CONST EFI_TLS_CIPHER *) Data;
     CipherCount = DataSize / sizeof (EFI_TLS_CIPHER);
     for (Index = 0; Index < CipherCount; Index++) {
-      *(CipherId +Index) = HTONS (*(((UINT16 *) Data) + Index));
+      CipherId[Index] = ((TlsCipherList[Index].Data1 << 8) |
+                         TlsCipherList[Index].Data2);
     }
 
     Status = TlsSetCipherList (Instance->TlsConn, CipherId, CipherCount);