zenfone9: Remove obsolete dex settings

This block is completely redundant because..
- WITH_DEXPREOPT := true is the default
- WITH_DEXPREOPT_PIC is never read
- DEX_PREOPT_DEFAULT := nostripping has no effect when the
  BOARD_USES_SYSTEM_OTHER_ODEX flag is set to true

Test: make
Change-Id: Ic9b5620bbaaf86d592edf133a5b7c44975309b4d
1 file changed