mm/thp: drop unused trace events hugepage_[invalidate|splitting]

The trace events hugepage_[invalidate|splitting], were added via the
commit 9e813308

 ("powerpc/thp: Add tracepoints to track hugepage
invalidate").  Afterwards their call sites i.e
trace_hugepage_[invalidate|splitting] were just dropped off, leaving
these trace points unused.

Link: https://lkml.kernel.org/r/1641546351-15109-1-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>