o add snes fatfs dummy

o add fatfs custom chip to bsnes
o finishes fatfs linux backend smaple

snes/fatfstest/pad.c

@@ -0,0 +1,17 @@
+#include "data.h";
+#include "pad.h";
+
+void enablePad(void) {
+	// Enable pad reading and NMI
+	*(byte*)0x4200 = 0x81;
+}
+
+padStatus readPad(byte padNumber) {
+	word test;
+	padStatus *status;
+	padNumber = padNumber << 1;
+	test = (word) *(byte*)0x4218+padNumber << 8;
+	test |= (word) *(byte*)0x4219+padNumber;
+	status = (padStatus *) &test;
+	return *status;
+}