N800 logs this message on boot:

[    0.182281] omap_hwmod: iva: cannot be enabled for reset (3)

Fix by creating basic IVA1 and DSP hwmods for OMAP2420, and a basic IVA2
hwmod for OMAP2430.  There is still more information to be added, but
this should resolve the immediate issue.
Signed-off-by: Paul Walmsley <paul@pwsan.com>