Use new LOOP_CONFIGURE ioctl for configuring loop devices.

This ioctl is a lot faster than LOOP_SET_FD/LOOP_SET_STATUS64, and
significantly improves boot time.  It may not be supported on all
devices, so we need to maintain the "legacy" way of configuring loop

Bug: 148607611
Bug: 161575393
Test: boot on device with/without LOOP_CONFIGURE
Change-Id: Iea501fabc1b83fd4e90436fa04b45c7434c069a6
1 file changed