Changed several char arrays all around the code to const char pointers, debloats the executable file from 8.7 MB to 5.6 MB;

Replaced the Cirrus Logic code with the latest code from TheCollector1995 - the CL-GD 5428 is now fully working, as is the CL-GD 5429;
Minor clean-up in the AHA/BusLogic BIOS commands code;
Slightly rewritten mem_readb_phys_dma() and mem_writeb_phys_dma().

src/video/vid_cl54xx.h

@@ -0,0 +1,5 @@
+/* Copyright holders: Sarah Walker
+   see COPYING for more details
+*/
+extern device_t gd5428_device;
+extern device_t gd5429_device;