Ignore UDP offload test on kernel which is older than 4.14

Kernel version which is older than 4.14 doesn't support UDP offload
absolutely. Kernel version which is between 4.14 and 5.8 support UDP
offload probably. Simply set kernel 4.14 to be threshold first and
monitor on what devices tests fail for improving the offload support
checking.

Also fix a minor bug which UDP tethering without offload is not tested
on R.

Bug: 230359047
Test: atest EthernetTetheringTest
Change-Id: Ieb181d1b5ed67b922e18ce77a9c96208b2984d10
(cherry picked from commit 08c48a3dff1ff913f882c562fcc3326dd39a4440)
Merged-In: Ieb181d1b5ed67b922e18ce77a9c96208b2984d10
1 file changed