MIPS: RB532: Fix init of rb532_dev3_ctl_res

This register just contains the address of the actual resource, so
initialisation has to be the same as cf_slot0_res and nand_slot0_res.

Signed-off-by: Phil Sutter <n0-1@freewrt.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>