Revert to standard libhardware_legacy.

Marvell specific wifi driver code is shipped in the device directory.
Also, added detail to the README.

Change-Id: I9bfe9b0ae060ae9e88ffab3303b3dcadfcf8cfa4
Correct typo for libhardware_legacy repository

Change-Id: I1a5211bf6886c86f7f83e36d2ff81afd98a85880
Merge branch 'ashcharles-master' into gumdroid-4.3_r3.1