uio_mf624: Align memory regions to page size and set correct offsets

mf624 card has its registers not aligned to pages. Since commit
b6550287 ("uio: we cannot mmap unaligned page contents") mmap()ing
mf624 registers fails, because now the uio drivers must set
uio_mem->addr to be page-aligned.

We align the address here and set the newly introduced offs field to
the offset of the mf264 registers within the page so that userspace
can find the address of the mmap()ed register by reading
/sys/class/uio/uio?/maps/map?/offset.

Tested with real mf624 card.

Signed-off-by: Michal Sojka <sojkam1@fel.cvut.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>