inputflinger fuzzers: tidy up kValid{Types,Codes}

SYN_REPORT is not a valid event type (i.e. it's not an evdev axis or one
of the additional event codes added by EventHub), so it shouldn't be in
kValidTypes.

Also remove a duplication of SYNC_MT_REPORT from kValidCodes.

Bug: 264582512
Test: build and run inputflinger_multitouch_input_fuzzer
Change-Id: I5f9219b7060d0b5cf0f36746502d7a400556a5cf