types.hpp: Added Platform type for PIO

MRAA C++ getPlatformType casts the return from mraa_get_platform_type()
to a Platform enum (which did not exist in C++ for AT).  Added enum type
to types.hpp which corresponds to the C enum type.

Signed-off-by: Noel Eck <noel.eck@intel.com>

api/mraa/types.hpp

@@ -59,6 +59,7 @@ typedef enum {
 
     GENERIC_FIRMATA = 1280,    /**< Firmata uart platform/bridge */
 
+    ANDROID_PERIPHERALMANAGER = 95, /**< Android Things peripheral manager platform */
     NULL_PLATFORM = 98,
     UNKNOWN_PLATFORM =
     99 /**< An unknown platform type, typically will load INTEL_GALILEO_GEN1 */