mmap-window: Fix 'mmap_window__pos_in_region'
mmap-window: Fix 'mmap_window__pos_in_region'

This corrects the failing scenario 'Significantly smaller window
length than file size'.

Signed-off-by: Jussi Virtanen <688853f2098600ecc93a73ab459c4906661052bb@reaktor.fi>
Signed-off-by: Pekka Enberg <add4fcd06328a394f0ad91feda7ee057316dc5ed@kernel.org>

penberg/pstore,penberg/pstore,penberg/pstore,penberg/pstore