pagemap: fix 32-bit pagemap regression

The large pages fix from bcf8039ed45 broke 32-bit pagemap by pulling the
pagemap entry code out into a function with the wrong return type.
Pagemap entries are 64 bits on all systems and unsigned long is only 32
bits on 32-bit systems.

Signed-off-by: Matt Mackall <[e-mail]>
Reported-by: Doug Graham <[e-mail]>
Cc: Alexey Dobriyan <[e-mail]>
Cc: Dave Hansen <[e-mail]>
Cc: <[e-mail]> [2.6.26.x, 2.6.27.x]
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

fs/proc/task_mmu.c

···
 	return swp_type(e) | (swp_offset(e) << MAX_SWAPFILES_SHIFT);
 }
 
-static unsigned long pte_to_pagemap_entry(pte_t pte)
+static u64 pte_to_pagemap_entry(pte_t pte)
 {
-	unsigned long pme = 0;
+	u64 pme = 0;
 	if (is_swap_pte(pte))
 		pme = PM_PFRAME(swap_pte_to_pagemap_entry(pte))
 			| PM_PSHIFT(PAGE_SHIFT) | PM_SWAP;