New patch for sms.c/sg1000.c: add new drivers, SMSJ rapid, SG1000 exp. slot

[enikland]

Micko asked me to post a diff here as an alternative for patch submission. The diff isn't anymore based on an updated mame tree, mainly due to my limited Internet access, but I hope it still applies to the current tree with some minimal offsets. Changelog:

• Create a SG-1000 expansion slot.
• Hook up the SG-1000 expansion slot to sg1000.cpp and sms.cpp (sg1000m3).
• Split the sk1100 code from sg1000.cpp and attach it to the new expansion slot.
• Create a new FM Sound Unit device and attach it to the new expansion slot.
• For the sc3000 driver, re-add sk1100 as a fixed SG-1000 expansion device.
• Add sg1000 software list to sg1000m3 and Japanese/Korean SMS drivers.
• Remove some mirrors for ports $DC/$DD on SMSJ based on Charles' hw tests.
• Add basic C-Sync callback to 315_5124.cpp, based on Charles' hw tests.
• Add built-in Rapid Fire (uses C-Sync) for SMSJ and Korean SMS1 drivers.
• Add new SMS drivers due to XTAL differences:

sms1br - Tec Toy Master System I (Brazil) sms2br - Tec Toy Master System II (Brazil) smsbr - Tec Toy Master System III Compact (Brazil) sms1paln - Tec Toy Master System I (PAL-N) sms2paln - Tec Toy Master System II (PAL-N) smspaln - Tec Toy Master System III Compact (PAL-N)

Brazil is PAL-M TV system, but I decided to call it by the country name, seems to be better recognizable and for emulation looks more like a NTSC system. PAL-N is used in Argentina, Paraguay and Uruguay and looks closer to the European PAL system when compared to PAL-M.

PS: I had to upload using TXT format, github said it also supports ZIP but didn't work. mame_sms_paldrivers_sgexp_rfire_diff.txt

Enik

[enikland]

The changes have been committed by etabeta78. Thanks!