Add page info in each segment if carrier does not support EMS.

If EMS is not supported, framework breaks down EMS into single segment
SMS and adds page info " x/y".

In the case of UCS2 encoding type, we need 8 bytes for this, but we
only have 6 bytes from UDH, so truncate the limit for each segment by
2 bytes (1 char).

Change-Id: Ie4f7e233155ce392c14ae75946c9d62d4897013c