Tidy up #ifdeffery for i2c speed

i2c.c

@@ -25,17 +25,12 @@ void init_i2c(void)
 {
 	IREG(I2CONSET) = 0x40; /* Enable I2C ready for Master Tx */
 	/* Set up for just under 400kHz */
-#if 0
+#ifdef I2C_FAST
 	IWREG(I2SCLL) = (25 * 100);
 	IWREG(I2SCLH) = (12 * 100);
 #else
-# if 0
-	IWREG(I2SCLL) = 1475; /* ~5kHz */
-	IWREG(I2SCLH) = 1475;
-# else
 	IWREG(I2SCLL) = 73; /* ~100kHz */
 	IWREG(I2SCLH) = 73;
-# endif
 #endif
 }