KVM: PPC: Book3S: Add support for ibm,int-on/off RTAS calls

This adds support for the ibm,int-on and ibm,int-off RTAS calls to the
in-kernel XICS emulation and corrects the handling of the saved
priority by the ibm,set-xive RTAS call.  With this, ibm,int-off sets
the specified interrupt's priority in its saved_priority field and
sets the priority to 0xff (the least favoured value).  ibm,int-on
restores the saved_priority to the priority field, and ibm,set-xive
sets both the priority and the saved_priority to the specified
priority value.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/arch/powerpc/kvm/book3s_xics.h b/arch/powerpc/kvm/book3s_xics.h
index c816c5a..e4fdec3 100644
--- a/arch/powerpc/kvm/book3s_xics.h
+++ b/arch/powerpc/kvm/book3s_xics.h
@@ -36,7 +36,7 @@
 	u32 number;
 	u32 server;
 	u8  priority;
-	u8  saved_priority; /* currently unused */
+	u8  saved_priority;
 	u8  resend;
 	u8  masked_pending;
 	u8  asserted; /* Only for LSI */