encore: don't create /rom world-writable

Change-Id: I7d96cc933a1a6bc36312ef9d0ac1f88890fde2f1
Revert "Use a separate kernel config for CM10.2 builds"

With the end of CM10.1.x stable releases, we're free to break the kernel
ABI, so we're back to having a single config for CM10.1+.

This reverts commit 9a2ab05c01ee27fdbafee5a50174cfb32ba6b0e1.
Build with new encore-omap3-3.0.y kernel branch

Change-Id: I480102a666764ba66873897a30d0111e2e120111
Reduce frame rate reported by framebuffer HAL to 54 Hz

This matches a corresponding kernel change to run the panel at 54 Hz
(allowing us to reduce the pixel clock to allow downscaling of larger
images).

Change-Id: Ib3e6ce2e2ac337fc5dfb2b02ccd31a708decda7b
Add <linux/omapfb.h> header needed for hwcomposer
Enable building of hwcomposer.omap3
Build audio HAL components from source instead of using prebuilts