minixfs: use offset_in_page()

It's cheaper and more idiomatic than subtracting page_address()
of the corresponding page...

Reviewed-by: Fabio M. De Francesco <fabio.maria.de.francesco@linux.intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2023-03-06 11:35:29 -05:00
commit 4812509e91