mm: optimize pfn calculation in online_page()
mm: optimize pfn calculation in online_page()

If CONFIG_FLATMEM is enabled pfn is calculated in online_page() more than
once.  It is possible to optimize that and use value established at
beginning of that function.

Signed-off-by: Daniel Kiper <f87bce239c2d929a7b9d096e345809271dca1b0e@net-space.pl>
Acked-by: Dave Hansen <bfcdf3e6ca6cef45543bfbb57509c92aec9a39fb@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <634f508bd7c47cf0ee4126243675c3e598920fbc@jp.fujitsu.com>
Cc: Wu Fengguang <24f7fe9d205c8a9f6ade0c2894e14303ca16087f@intel.com>
Cc: Mel Gorman <2f629c4d93e35c3d371f0463b040c6ef04a5c1e5@csn.ul.ie>
Cc: Christoph Lameter <ef3ecccf258fa062c5c6521a4887d40541963af7@linux.com>
Acked-by: David Rientjes <d8cd2994e15bc61ddb2b113030bda55eebc3a0fe@google.com>
Reviewed-by: Jesper Juhl <7323a5431d1c31072983a6a5bf23745b655ddf59@chaosbits.net>
Signed-off-by: Andrew Morton <5c1e68b099950c134891f0b6e179498a8ebe9cf9@linux-foundation.org>
Signed-off-by: Linus Torvalds <69652caca27c8b940640ad396ab71f93cacec34f@linux-foundation.org>

TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs