By default, only consider AMD GPU's in RSMI device list (#36)

With newly added initialization parameters that can be
passed to rsmi_init(), you can tell RSMI to consider other
devices.

Also:
-fixed incorrect header file name that would break in C
builds
-modified rsmi_init() and rsmi_shut_down() to reinitialize and
clear static structures

include/rocm_smi/rocm_smi.h

@@ -113,6 +113,29 @@ typedef enum {
   RSMI_STATUS_UNKNOWN_ERROR = 0xFFFFFFFF,  //!< An unknown error occurred
 } rsmi_status_t;
 
+typedef enum {
+  RSMI_INIT_FLAG_ALL_GPUS      = 0x1,    //!< Attempt to add all GPUs found
+                                         //!< (including non-AMD) to the list
+                                         //!< of devices from which SMI
+                                         //!< information can be retrieved. By
+                                         //!< default, only AMD devices are
+                                         //!<  ennumerated by RSMI.
+} rsmi_init_flags_t;
+
+/**
+ * @brief Initialization flags
+ * 
+ * Initialization flags may be OR'd together and passed to ::rsmi_init().
+ */
+typedef enum {
+  RSMI_INIT_FLAG_ALL_GPUS      = 0x1,    //!< Attempt to add all GPUs found
+                                         //!< (including non-AMD) to the list
+                                         //!< of devices from which SMI
+                                         //!< information can be retrieved. By
+                                         //!< default, only AMD devices are
+                                         //!<  ennumerated by RSMI.
+} rsmi_init_flags_t;
+
 /**
  * @brief Initialization flags
  *