Stop O_CREAT logspam in permissive mode.

In permissive mode we get more spurious denials when O_CREAT is used
with an already-existing file. They're harmless so we don't need to
audit them.

Example denials:
denied { add_name } for name="trigger" scontext=u:r:init:s0 tcontext=u:object_r:sysfs_leds:s0 tclass=dir permissive=1
denied { create } for name="trigger" scontext=u:r:init:s0 tcontext=u:object_r:sysfs_leds:s0 tclass=file permissive=1

Bug: 72643420
Bug: 74182216

Test: Device boots, denials gone.
Change-Id: I54b1a0c138ff5167f1d1d12c4b0b9e9afaa5bca0