Made timeouts configurable, untested

nuttx/arch/arm/src/stm32/stm32_i2c.c

@@ -2013,7 +2013,7 @@ int up_i2creset(FAR struct i2c_dev_s * dev)
 
           /* Give up if we have tried too hard */
 
-          if (clock_count++ > 1000)
+          if (clock_count++ > CONFIG_STM32_I2CTIMEOTICKS)
             { 
               goto out;
             }

nuttx/configs/px4fmu/nsh/defconfig

@@ -372,7 +372,8 @@ CONFIG_I2C_POLLED=y
 CONFIG_I2C_TRANSFER=y
 CONFIG_I2C_TRACE=n
 CONFIG_I2C_RESET=y
-
+# XXX fixed per-transaction timeout
+CONFIG_STM32_I2CTIMEOMS=10
 
 
 # XXX re-enable after integration testing