Use hal-rootstrap package for build and change hal_backend_power_funcs memory allocat...

Use hal-rootstrap package for build and change hal_backend_power_funcs memory allocation/free

hal-roostrap package contains the allowed and maintained files
to build hal-backend package. In order to keep ABI (Application Binary
Interface) compatibility between platfrom and hal image,
must use only hal-rootstrap pacakge for build.

And chagnge the memory allocation/free way of hal_backend_power_funcs
in order to support new 1-platform Multi-HAL Interface approach.

Change-Id: I15707fae89d53a5702be1bfe34e9779325319253
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>