parisc: fix wrong page aligned size calculation in ioremapping code

parisc __ioremap(): fix off-by-one error in page alignment of allocation
size for sizes where size%PAGE_SIZE==1.

Signed-off-by: Florian Zumbiehl <florz@florz.de>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Acked-by: Helge Deller <deller@gmx.de>
Tested-by: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>