Add DTCM to DS/DSi Memory Maps

[CasualPokePlayer]

https://problemkaputt.de/gbatek.htm#dsmemorycontrolcacheandtcm https://problemkaputt.de/gbatek.htm#armcp15tightlycoupledmemorytcm

TCM is high speed memory on the ARM9 CPU itself. There are two types of TCM, one meant for Instructions (ITCM) and one meant for Data (DTCM). ITCM is probably unlikely to be useful for achievements, but DTCM seems to be useful. Okamiden for the DS appears to store all important savefile flags in this region rather than in Main RAM.

There is a question however where exactly should it be put. Should it be placed right after the Main RAM for each console (which would result in a odd memory map when comparing the two, and could be potentially problematic if you want to support running DSi enhanced games in either DS or DSi mode), or should it be placed after what would be the Main RAM for DSi, and leave a 12MiB hole for DS?