Revert "crash_dump: during early boot, output to kmsg on userdebug."

This reverts commit bf2dd482.

Addresses:
avc: denied { relabelto } for name="kmsg_debug" dev="tmpfs" ino=10642
scontext=u:r:init:s0 tcontext=u:object_r:device:s0 tclass=chr_file

Bug: 62101480, 35197529
Test: build and boot device. Verify selinux denial no longer occurs.
Change-Id: I28ce16f50eec20ef15c1721f41b66f22a84e7cca