rocr: set underlying type of hsa_region_info_t, hsa_amd_region_info_t

When an enum's backing type is not set explicitly it is undefined
behavior to load a value that is not one of the specific values
it was defined with.

See https://eel.is/c++draft/expr.static.cast#9

runtime/hsa-runtime/inc/hsa.h

@@ -3269,7 +3269,7 @@ typedef enum {
 /**
  * @brief Attributes of a memory region.
  */
-typedef enum {
+typedef enum : int {
   /**
    * Segment where memory in the region can be used. The type of this
    * attribute is ::hsa_region_segment_t.

runtime/hsa-runtime/inc/hsa_ext_amd.h

@@ -774,7 +774,7 @@ typedef struct hsa_amd_hdp_flush_s {
 /**
  * @brief Region attributes.
  */
-typedef enum hsa_amd_region_info_s {
+typedef enum hsa_amd_region_info_s : int {
   /**
    * Determine if host can access the region. The type of this attribute
    * is bool.