[PATCH] remove linux/pagemap.h from linux/swap.h

sparc can not include linux/pagemap.h because of the following circular
dependency:

asm-sparc/pgtable include linux/swap.h
linux/swap.h include now linux/pagemap.h
linux/pagemap.h include linux/mm.h
linux/mm.h include asm/pgtable.h

It needs to have the swp_entry_t type fully visible in pgtable.h,
we can't work around this using macros.

Signed-off-by: Olaf Hering <olh@suse.de>
Cc: William Lee Irwin III <wli@holomorphy.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>