Fix issues introduced in 57b6135e54

- std=c++.. is not required because CMAKE_CXX_STANDARD is set
- nullptr check breaks the test because we rely on nullptr as an api for
  checking feature availability.
- enum number setting is unnecessary

Change-Id: I393e6dd3f292b7fa4198302f140c0443ba5e50f5
Signed-off-by: Galantsev, Dmitrii <dmitrii.galantsev@amd.com>

include/rocm_smi/rocm_smi.h

@@ -363,16 +363,16 @@ typedef rsmi_clk_type_t rsmi_clk_type;
  */
 typedef enum {
   RSMI_COMPUTE_PARTITION_INVALID = 0,
-  RSMI_COMPUTE_PARTITION_CPX = 1,    //!< Core mode (CPX)- Per-chip XCC with
-                                     //!< shared memory
-  RSMI_COMPUTE_PARTITION_SPX  = 2,   //!< Single GPU mode (SPX)- All XCCs work
-                                     //!< together with shared memory
-  RSMI_COMPUTE_PARTITION_DPX  = 3,   //!< Dual GPU mode (DPX)- Half XCCs work
-                                     //!< together with shared memory
-  RSMI_COMPUTE_PARTITION_TPX = 4,    //!< Triple GPU mode (TPX)- One-third XCCs
-                                     //!< work together with shared memory
-  RSMI_COMPUTE_PARTITION_QPX = 5,    //!< Quad GPU mode (QPX)- Quarter XCCs
-                                     //!< work together with shared memory
+  RSMI_COMPUTE_PARTITION_CPX, //!< Core mode (CPX)- Per-chip XCC with
+                              //!< shared memory
+  RSMI_COMPUTE_PARTITION_SPX, //!< Single GPU mode (SPX)- All XCCs work
+                              //!< together with shared memory
+  RSMI_COMPUTE_PARTITION_DPX, //!< Dual GPU mode (DPX)- Half XCCs work
+                              //!< together with shared memory
+  RSMI_COMPUTE_PARTITION_TPX, //!< Triple GPU mode (TPX)- One-third XCCs
+                              //!< work together with shared memory
+  RSMI_COMPUTE_PARTITION_QPX, //!< Quad GPU mode (QPX)- Quarter XCCs
+                              //!< work together with shared memory
 } rsmi_compute_partition_type_t;
 /// \cond Ignore in docs.
 typedef rsmi_compute_partition_type_t rsmi_compute_partition_type;
@@ -680,8 +680,8 @@ typedef enum {
  */
 typedef enum _RSMI_IO_LINK_TYPE {
   RSMI_IOLINK_TYPE_UNDEFINED      = 0,          //!< unknown type.
-  RSMI_IOLINK_TYPE_PCIEXPRESS     = 1,          //!< PCI Express
-  RSMI_IOLINK_TYPE_XGMI           = 2,          //!< XGMI
+  RSMI_IOLINK_TYPE_PCIEXPRESS,                  //!< PCI Express
+  RSMI_IOLINK_TYPE_XGMI,                        //!< XGMI
   RSMI_IOLINK_TYPE_NUMIOLINKTYPES,              //!< Number of IO Link types
   RSMI_IOLINK_TYPE_SIZE           = 0xFFFFFFFF  //!< Max of IO Link types
 } RSMI_IO_LINK_TYPE;