fix for virtualbox-70 after current commit a3a88ed

In case anyone else is stuck on this ..

Recent changes in -current to remove vm_page_prev and vm_page_next break 
compilation and loading of the virtualbox kernel modules.

This patch moves the troublesome call to the new KPI. I only tested on 
virtualbox-70 but other versions probably need similar adjustments.

*** ./src/VBox/Runtime/r0drv/freebsd/memobj-r0drv-freebsd.c.orig 
Sat Apr 19 13:11:03 2025
--- ./src/VBox/Runtime/r0drv/freebsd/memobj-r0drv-freebsd.c     Sat Apr 
19 14:43:33 2025
***************
*** 78,83 ****
--- 78,86 ----
   #include <iprt/process.h>
   #include "internal/memobj.h"

+ #if __FreeBSD_version >= 1500038
+ #include <vm/vm_radix.h>
+ #endif

  
/*********************************************************************************************************************************
   *   Structures and Typedefs 
                                                            *
***************
*** 201,209 ****
--- 204,219 ----
   #if __FreeBSD_version < 1000000
               vm_page_lock_queues();
   #endif
+ #if __FreeBSD_version >= 1500038
+             struct pctrie_iter pages;
+
+           vm_page_iter_init(&pages, pMemFreeBSD->pObject);
+           VM_RADIX_FORALL(pPage, &pages)
+ #else
               for (vm_page_t pPage = 
vm_page_find_least(pMemFreeBSD->pObject, 0);
                    pPage != NULL;
                    pPage = vm_page_next(pPage))
+ #endif
               {
                   vm_page_unwire(pPage, 0);
               }