stm32: use stm32-rs SVDs which are of much higher quality

This commit changes the number of wait states for the stm32f103 chip to
2 instead of 4. This gets it back in line with the datasheet, but it
also has the side effect of breaking I2C. Therefore, another (seemingly
unrelated) change is needed: the i2cTimeout constant must be increased
to a higher value to adjust to the lower flash wait states - presumably
because the lower number of wait states allows the chip to run code
faster.

src/machine/board_lgt92.go

@@ -55,7 +55,7 @@ var (
 	// Console UART (LPUSART1)
 	UART0 = UART{
 		Buffer:          NewRingBuffer(),
-		Bus:             stm32.LPUSART1,
+		Bus:             stm32.LPUART1,
 		AltFuncSelector: 6,
 	}