Fix timeout issue of pti-rtp release job

Fix timeout issue of pti-rtp release job

The pti-rtp-shell-release-master job is to build and push  artifacts of
pti-rtp project to nexus3 repo. The building time takes longer time than
expected, so we have to increase the timeout to 48 hours
according to the building stats: it takes 35hours with building 70% of image.

https://jenkins.o-ran-sc.org/view/pti-rtp/job/pti-rtp-shell-release-master/2/

Issue-ID: INF-182
Signed-off-by: Bin Yang <bin.yang@windriver.com>
Change-Id: I65a0e8282285ca5a23591775015dc68164ca1bdb