x86/irq: Prepare consolidation of irq_alloc_info

struct irq_alloc_info is a horrible zoo of unnamed structs in a union. Many
of the struct fields can be generic and don't have to be type specific like
hpet_id, ioapic_id...

Provide a generic set of members to prepare for the consolidation. The goal
is to make irq_alloc_info have the same basic member as the generic
msi_alloc_info so generic MSI domain ops can be reused and yet more mess
can be avoided when (non-PCI) device MSI support comes along.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20200826112331.849577844@linutronix.de

arch/x86/include/asm/hw_irq.h

@@ -44,10 +44,25 @@ enum irq_alloc_type {
 	X86_IRQ_ALLOC_TYPE_HPET_GET_PARENT,
 };
 
+/**
+ * irq_alloc_info - X86 specific interrupt allocation info
+ * @type:	X86 specific allocation type
+ * @flags:	Flags for allocation tweaks
+ * @devid:	Device ID for allocations
+ * @hwirq:	Associated hw interrupt number in the domain
+ * @mask:	CPU mask for vector allocation
+ * @desc:	Pointer to msi descriptor
+ * @data:	Allocation specific data
+ */
 struct irq_alloc_info {
 	enum irq_alloc_type	type;
 	u32			flags;
-	const struct cpumask	*mask;	/* CPU mask for vector allocation */
+	u32			devid;
+	irq_hw_number_t		hwirq;
+	const struct cpumask	*mask;
+	struct msi_desc		*desc;
+	void			*data;
+
 	union {
 		int		unused;
 #ifdef	CONFIG_HPET_TIMER
@@ -87,11 +102,6 @@ struct irq_alloc_info {
 			unsigned long	uv_offset;
 			char		*uv_name;
 		};
-#endif
-#if IS_ENABLED(CONFIG_VMD)
-		struct {
-			struct msi_desc *desc;
-		};
 #endif
 	};
 };