Add missed firmwares.

Change-Id: I9cf83d364cb70239d7e4c01c23b69fb7b5d9a9b9
Use 4.2 sensors.msm8974.so to fix camera reopen crash.

Change-Id: I41d03097ec81c6a5e68ad2734a4289e59bf7f0e4
Build libskia.so from source.

The library /system/vendor/lib/libqc-opt.so relies on the stock libskia.so
because of some symbol called "co_node." So we edit libqc-opt.so's linked
libraries to change libskia to libLGsk.so (must be same size) and rename
LG's libskia.so to libLGsk.so, and build libskia.so from source. Now
everybody is happy.

Change-Id: I8613052df6338d7c0e7b3c41bea6cd498b35a6e1