cps1/cps15: support for scene simulations

[jotego]

cps1/cps15 cores do not support jtsim scene simulations. Support for this would help with issues #157, #657 and #667. This system has VRAM and OBJ RAM implemented in the SDRAM.

Steps to add support:

• increase JTFRAME_IOCTL_RD to cover the current 128 bytes (used by Pang! 3) plus the space needed by the BRAM dump
• multiplex the address ports for slots 1 and 2 of u_bank0 in jtcps1_sdram such that when ioctl_ram is high, ioctl_addr is sent to those slots. Only one slot should be active during readings, depending on the ioctl_addr.
• prepare the dump2bin.sh script that splits the .RAM save file into several files. Modify jtcps1_dma so each module loads the relevant file in simulation. Commit dump2bin.sh to git
• adjust the verilog files as needed so when running a scene video data is not overwritten by a DMA event

[jotego]

as the #157 issue is fixed, we'll postpone this task until needed again.