Hammerhead - Enable slimport detection after boot completion

To prevent slimport error during boot up, wait until boot
completion before start slimport detection.

Bug: 11518558

Change-Id: I8e23785eb851fb552eb08acf846714cd46d19fc4
Signed-off-by: MURA Stefano [STELIX PippoX3] <ssspinni@gmail.com>