vregion: remove need to include rtos/alloc.h in !CONFIG_SOF_VREGIONS build

Remove need to include rtos/alloc.h in !CONFIG_SOF_VREGIONS build. We
do not need the dummy vregion objects for anything, so get rid of
them. From now on creating a vregion object when CONFIG_SOF_VREGIONS
is not defined will fail.

Signed-off-by: Jyri Sarha <jyri.sarha@linux.intel.com>

Author: Jyri Sarha

src/include/sof/lib/vregion.h

@@ -125,29 +125,20 @@ void vregion_mem_info(struct vregion *vr, size_t *size, uintptr_t *start);
 
 #else /* CONFIG_SOF_VREGIONS */
 
-#include <rtos/alloc.h>
-
 struct vregion {
 	unsigned int use_count;
 };
 
 static inline struct vregion *vregion_create(size_t lifetime_size, size_t interim_size)
 {
-	struct vregion *vr = rmalloc(0, sizeof(*vr));
-
-	vr->use_count = 1;
-	return vr;
+	return NULL;
 }
 static inline struct vregion *vregion_get(struct vregion *vr)
 {
-	if (vr)
-		vr->use_count++;
 	return vr;
 }
 static inline struct vregion *vregion_put(struct vregion *vr)
 {
-	if (vr && !--vr->use_count)
-		rfree(vr);
 	return vr;
 }
 static inline void *vregion_alloc(struct vregion *vr, enum vregion_mem_type type, size_t size)