Start teaching sh3 code about STX7105.

Kernel option STX7105 to select CPU product (TODO: all of the options
that select CPU product should be defflag'ed to opt_cputype.h).

The ST40 cache sizes can be customized for each product. For now just
hardcode the STx7105 values in the switch, but may be they should be
kernel options.

Add placeholders/boilerplate for NextVoD.

STMicroelectronics support needs to be written for both the CPU and
devices. This config and related files is absolute bare bones to get
a scaffolding kernel to compile to actually work on that support.
Don't hold your breath.