[PATCH] ia64: fix ia32 partial-page map support for overlapping mmaps

- Handle the overlapping mmaps in the MAP_FIXED case
- Handle unmaps correctly i.e. call __ia32_delete_pp_range()
- There are now three clear entry points into the pp manipulation code
        - ia32_set_pp
        - ia32_unset_pp
        - ia32_compare_pp
- Rename internal functions to __ia32_*pp_*
- Grab mmap_sem just once at the main entry point
Signed-off-by: Gordon Jin <gordon.jin@intel.com>
Signed-off-by: Arun Sharma <arun.sharma@intel.com>
Signed-off-by: David Mosberger <davidm@hpl.hp.com>