Also fix use of weak stm32 internal pullup

drivers/arm/i2c_master.c

@@ -51,8 +51,8 @@ void i2c_init(void)
 
   chThdSleepMilliseconds(10);
  
-  palSetPadMode(GPIOB, 6, PAL_MODE_ALTERNATE(4) | PAL_STM32_OTYPE_OPENDRAIN | PAL_STM32_PUPDR_PULLUP);
-  palSetPadMode(GPIOB, 7, PAL_MODE_ALTERNATE(4) | PAL_STM32_OTYPE_OPENDRAIN | PAL_STM32_PUPDR_PULLUP);
+  palSetPadMode(GPIOB, 6, PAL_MODE_ALTERNATE(4) | PAL_STM32_OTYPE_OPENDRAIN);
+  palSetPadMode(GPIOB, 7, PAL_MODE_ALTERNATE(4) | PAL_STM32_OTYPE_OPENDRAIN);
 
   //i2cInit(); //This is invoked by halInit() so no need to redo it.
 }