l2c: Change std::vector to uint16[] in the tL2C_LCB

Since there are places where memset is done on tL2C_LCB
we can't keep std::vector in this struct

Tag: #feature
Bug: 159786353
Sponsor: jpawlowski@
Test: compile & manual

Change-Id: I2a9795e3c7dbe280b17725eac6333744440e89df