[J-core] qemu support

[Christopher Friedt]

There are a mix of SH4 and SH4A cores in the currently supported -cpu options:

$ qemu-system-sh4 -cpu help
SH7750R
SH7751R
SH7785

There is a list that provides seemingly good coverage of the available
families here [1].

Does anyone with some familiarity of SH2 have any suggestions of which
cpu would be least complicated for adding to Qemu?

I'm leaning toward SH7046, since I do not necessarily care for flash
at the moment.

[1] http://www.renesas.com/products/mpumcu/superh/index.jsp