staging: fsl-mc: fix resource_size.cocci warnings

 Use resource_size function on resource object
 instead of explicit computation.

Generated by: scripts/coccinelle/api/resource_size.cocci

Fixes: a037b7ec2eb7 ("staging: fsl-mc: allow the driver compile multi-arch")
CC: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Signed-off-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>