MTU should be 1358 as per 3GPP standards, especially for LTE radio interfaces.

Change-Id: I5d3601b05a41d4c59cff3b39ddfb66d00cb23c45
Signed-off-by: Stacy Devino <swylie@oceusnetworks.com>

Patchset: 1
http://review.cyanogenmod.org/#/c/75075/