t6k11: use the gint array for variant detection
r61524: use true triple buffering by default
display: define DWIDTH and DHEIGHT
display: add C_RGB(r,g,b) (0 ≤ r,g,b ≤ 31) [fxcg50]
Currently there seems to be no DMA at all on fx9860g. Further
investigation would be required, because this would be the first major
difference between the SH7305's found in fx9860g and fxcg50 models.
An automated peripheral register discovery strategy might help, but
identifying discovered registers would be non trivial.
Also use the pruning ability of the Makefile to avoid troublesome
ifdef's in the code.