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