dev_ns: adopt the android logger driver

Adds device namespace info to android logger entries and filters entries
read by the device namespace in which the reader runs - so a process would
only see logs from its own namespace.

Adds an ioctl to android logger to select from which namespace log entries
should be read. This is useful to allow host to filter events from specific
namespace when reading from /dev/log/events.

Changelog:
[16-Aug-2013] v1 - initial version

Change-Id: I8457b4ab5c02d5d819a84a516c11575df15c832b
Signed-off-by: Amir Goldstein <amir@cellrox.com>
Signed-off-by: Oren Laadan <orenl@cellrox.com>