xive: Fix typos in comments
xive: Fix typos in comments

Fix a typo in comment about Presentation Controller Base Address Register
and another typo about code to configure the queue overflows.

Signed-off-by: Gustavo Romero <ce43015c4046df936ab2a5b45f555e3b8ab74301@linux.ibm.com>
Reviewed-by: Cédric Le Goater <2d8cace2254d4e43578d21933db015d84bcc468a@kaod.org>
Signed-off-by: Oliver O'Halloran <3dfaff8fa6ae977f042064a112a6aac576279b9b@gmail.com>

qemu/skiboot,legoater/skiboot,shenki/skiboot,open-power/skiboot,shenki/skiboot,legoater/skiboot,shenki/skiboot,legoater/skiboot,qemu/skiboot,qemu/skiboot,open-power/skiboot,shenki/skiboot,shenki/skiboot,qemu/skiboot,open-power/skiboot,legoater/skiboot,open-power/skiboot,legoater/skiboot,open-power/skiboot,qemu/skiboot