KVM: arm/arm64: vgic: Convert struct vgic_lr to use bitfields

As we're about to cram more information in the vgic_lr structure
(HW interrupt number and additional state information), we switch
to a layout similar to the HW's:

- use bitfields to save space (we don't need more than 10 bits
  to represent the irq numbers)
- source CPU and HW interrupt can share the same field, as
  a SGI doesn't have a physical line.
Reviewed-by: NAlex Bennée <alex.bennee@linaro.org>
Reviewed-by: NChristoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

include/kvm/arm_vgic.h

@@ -95,11 +95,15 @@ enum vgic_type {
 #define LR_STATE_ACTIVE		(1 << 1)
 #define LR_STATE_MASK		(3 << 0)
 #define LR_EOI_INT		(1 << 2)
+#define LR_HW			(1 << 3)
 
 struct vgic_lr {
-	u16	irq;
-	u8	source;
-	u8	state;
+	unsigned irq:10;
+	union {
+		unsigned hwirq:10;
+		unsigned source:3;
+	};
+	unsigned state:4;
 };
 
 struct vgic_vmcr {