sh4: CPU versioning.

sh4: CPU versioning.

Trivial patch adding CPU listing and the ability to do per-subtype
CVR/PVR/PRR values. Presently SH7750R and SH7751R definitions are
provided, as these are the ones in present use in-tree.

The CVR value for SH7751R is intentionally restricted so the kernel
boots, though this will want to be switched to the proper CVR value
once system emulation has sufficiently stabilized.

This also makes it trivial to abstract subtype specific registers like
MMU_PTEA and to set up feature bits in line with the kernel probing for
things like conditionalizing FPU/DSP context.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5133 c046a42c-6fe2-441c-8c8c-71466251a162