doxygen: score: Change no_cpu architecture group

Groups CPUContext and CPUInterrupt are now defined with a unique name
for this architecture group.
Update #3706.

cpukit/score/cpu/no_cpu/include/rtems/score/cpuimpl.h

@@ -84,7 +84,7 @@ register struct Per_CPU_Control *_CPU_Per_CPU_current asm( "rX" );
 #define _CPU_Get_thread_executing() ( _CPU_Per_CPU_current->executing )
 
 /**
- * @ingroup CPUContext
+ * @addtogroup RTEMSScoreCPUExampleContext
  *
  * @brief Clobbers all volatile registers with values derived from the pattern
  * parameter.
@@ -98,7 +98,7 @@ register struct Per_CPU_Control *_CPU_Per_CPU_current asm( "rX" );
 void _CPU_Context_volatile_clobber( uintptr_t pattern );
 
 /**
- * @ingroup CPUContext
+ * @addtogroup RTEMSScoreCPUExampleContext
  *
  * @brief Initializes and validates the CPU context with values derived from
  * the pattern parameter.