spcn: add definitions for the PRS command and modifiers
spcn: add definitions for the PRS command and modifiers

The structures and values from the SPCN specification document plus
the new PRS modifier 0x1C to retrieve the power supplies watts.

Signed-off-by: Cédric Le Goater <2d8cace2254d4e43578d21933db015d84bcc468a@fr.ibm.com>
Signed-off-by: Stewart Smith <ec31ab75ddf977353c8f660f92ea8b23f64aef25@linux.vnet.ibm.com>

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