iomap: Fix iomap_invalidatepage tracepoint

iomap: Fix iomap_invalidatepage tracepoint

This tracepoint is defined to take an offset in the file, not an
offset in the folio.

Fixes: 1ac994525b9d ("iomap: Remove pgoff from tracepoints")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Tested-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Acked-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Tested-by: Mike Marshall <hubcap@omnibond.com> # orangefs
Tested-by: David Howells <dhowells@redhat.com> # afs