Use resource_size function on resource object
 instead of explicit computation.

 The semantic patch that makes this change is available
 in scripts/coccinelle/api/resource_size.cocci.

 More information about semantic patching is available at
 http://coccinelle.lip6.fr/Signed-off-by: NThomas Meyer <thomas@m3y3r.de>
Signed-off-by: NRichard Kuo <rkuo@codeaurora.org>