Remove input plugins hard libudev dependency

Remove input plugins hard libudev dependency

libudev extends the base functionality of these plugins but should not
be mandatory as it is missing on many embedded devices that still
actually require input devices (keyboard and/or mouse and/or
touchscreen) support

Change-Id: Ieeb949f1af5e774578f689a63f47a8c48f546ac1
Reviewed-by: Girish Ramakrishnan <girish.1.ramakrishnan@nokia.com>