Use px4_config.h instead of nuttx/config.h

Modified code to use OS independent header file for config settings.

Signed-off-by: Mark Charlebois <charlebm@gmail.com>

src/drivers/mkblctrl/mkblctrl.cpp

@@ -41,7 +41,7 @@
  *
  */
 
-#include <nuttx/config.h>
+#include <px4_config.h>
 #include <drivers/device/i2c.h>
 #include <systemlib/param/param.h>
 

src/drivers/mkblctrl/mkblctrl_params.c

@@ -40,7 +40,7 @@
  * @author Marco Bauer <marco@wtns.de>
  */
 
-#include <nuttx/config.h>
+#include <px4_config.h>
 #include <systemlib/param/param.h>
 
 /**