ANDROID: misc: add debug-kinfo driver

Backup kernel information for bootloader usage.

  Specifics:

   - The kallsyms symbols for unwind_backtrace

   - Page directory pointer

   - UTS_RELEASE

   - BUILD_INFO(ro.build.fingerprint)

Bug: 170851792
Bug: 169101608
Signed-off-by: Jone Chou <jonechou@google.com>
Change-Id: Ida76bf90315652b8debc081a010bc5720a5a186e