slw: Simplify if-condition while adding idle states to device tree
slw: Simplify if-condition while adding idle states to device tree

if-condition in add_cpu_idle_state_properties which checks if a given idle
state is supported  is bloated with multiple  '&' and '||' operations.
Simplify by adding a mask variable and setting the relevant bits.
This patch does not change any functionality.

Acked-by: Michael Neuling <7b0ab45a730e48a69239010b5b8fe5fa4e8eaac6@neuling.org>
Signed-off-by: Shreyas B. Prabhu <fac76aafe57fc9acb24e05f5dba9b58a43a0a645@linux.vnet.ibm.com>
Signed-off-by: Stewart Smith <ec31ab75ddf977353c8f660f92ea8b23f64aef25@linux.vnet.ibm.com>

mikey/skiboot,open-power/skiboot,shenki/skiboot,mikey/skiboot,stewart-ibm/skiboot,qemu/skiboot,shenki/skiboot,open-power/skiboot,legoater/skiboot,qemu/skiboot,legoater/skiboot,legoater/skiboot,shenki/skiboot,mikey/skiboot,stewart-ibm/skiboot,legoater/skiboot,shenki/skiboot,qemu/skiboot,shenki/skiboot,open-power/skiboot,qemu/skiboot,open-power/skiboot,stewart-ibm/skiboot,qemu/skiboot,open-power/skiboot,legoater/skiboot