bsps: Rework cache manager implementation

The previous cache manager support used a single souce file
(cache_manager.c) which included an implementation header (cache_.h).
This required the use of specialized include paths to find the right
header file.  Change this to include a generic implementation header
(cacheimpl.h) in specialized source files.

Use the following directories and files:

* bsps/shared/cache

* bsps/@RTEMS_CPU@/shared/cache

* bsps/@RTEMS_CPU@/@RTEMS_BSP_FAMILY/start/cache.c

Update #3285.

bsps/sparc/leon2/start/cache.c

@@ -0,0 +1,51 @@
+/*
+ *  SPARC Cache Manager Support
+ */
+
+/*
+ * CACHE MANAGER: The following functions are CPU-specific.
+ * They provide the basic implementation for the rtems_* cache
+ * management routines. If a given function has no meaning for the CPU,
+ * it does nothing by default.
+ *
+ * FIXME: Some functions simply have not been implemented.
+ */
+
+#include <stddef.h>
+
+#define CPU_INSTRUCTION_CACHE_ALIGNMENT 0
+
+#define CPU_CACHE_SUPPORT_PROVIDES_RANGE_FUNCTIONS
+
+static inline void _CPU_cache_invalidate_entire_instruction ( void )
+{
+  __asm__ volatile ("flush");
+}
+
+static inline void _CPU_cache_invalidate_instruction_range(
+  const void *i_addr,
+  size_t      n_bytes
+)
+{
+  __asm__ volatile ("flush");
+}
+
+/* XXX these need to be addressed */
+
+static inline void _CPU_cache_freeze_instruction ( void )
+{
+}
+
+static inline void _CPU_cache_unfreeze_instruction ( void )
+{
+}
+
+static inline void _CPU_cache_enable_instruction ( void )
+{
+}
+
+static inline void _CPU_cache_disable_instruction (   void )
+{
+}
+
+#include "../../../shared/cache/cacheimpl.h"