In order to be usable for early boot code move the simple set_page_xxx()
function to header file. Also change the parameters, and the function names
slightly.

This is required since there aren't any struct pages available in early
boot code, and renaming of functions is done to make sure that all users
are converted to the new API.

Instead of a pointer to a struct page a virtual address is passed, and
instead of an order the number of pages for which the page state needs be
set.
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>