Add carrier config for exit hysteresis time

Add carrier config for exit hysteresis time which will
be used to decide hysteresis time while switching away from
opportunisitc network to a primary network

Bug: 135556490
Test: Make
Merged-In: Ic4916c11ae470f2440481670bc1e25f570e6ece4
Change-Id: Ic4916c11ae470f2440481670bc1e25f570e6ece4