Add --enable-mali20 as configure option

This option is used for Mali 400 API 20 (r3p2-01rel1) libs.
If not enabled, XBMC configure will report that GLES libs
do not exist.
[aml] add PivosPowerSyscall class to handle m3 suspend
[aml] rework m3 syspend/resume
Allow Powerdown menu for devices other than M1

Just because device can't power itself off, doesn't mean system shouldn't be given opportuntity to have a clean exit from xbmc.

This renables Powerdown menu so S95-xbmc script has a chance to run and dismount drives and removable media.

On M3 users will have to physically remove power to power off.
Disable suspend fuction
LINUX: Add config options for powermanagment