Plug memory leak in jumbo buffer allocation failure path.

Plug memory leak in jumbo buffer allocation failure path.
Patch in the PR was modified to check active jumbo buffers in use
and other possible jumbo buffer leak.

Jumbo buffer usage in lge(4) still wouldn't be reliable due to lack
of driver lock in local jumbo buffer allocator. Either introduce
a new lock to protect jumbo buffer or switch to UMA backed page
allocator for jumbo frame is required.

PR:	kern/78072