bme680: Support SoftI2C

src/driver/bme680_util.cc

 #include "arch.h"
+#if defined(MULTIPASS_ARCH_HAS_I2C) && !defined(DRIVER_SOFTI2C)
 #include "driver/i2c.h"
+#else
+#include "driver/soft_i2c.h"
+#endif
 #include <stdint.h>
 
 void bme680_delay_ms(uint32_t const period)