Remove old LOG_EVENT_* code from libsysutils

As a side effect, this change fixes
libbsysutils => liblog dependencies. LOG_EVENT_*
macros are not defined for liblog.vendor.

Test: BOARD_VNDK_VERSION=current mma
Bug: 33241851
Bug: 63034227
Change-Id: I3df700d97481ec9aa59cf1796da1e991af28bdf5