hv: pirq: do not indicate priority when allocate vector

It's not necessary to specify priority for dynamic allocated vector, because
nested irq is not supported on HV, and irq of any priority would cause VM exit.

This commit makes the following changes:
 - remove the argument indicating priority in struct irq_request_info and
   following functions:
    ptdev_activate_entry()
    find_available_vector()
    irq_desc_alloc_vector()
    normal_register_handler()
 - change the macro of vector ranges:
    VECTOR_DYNAMIC_START/END for dynamically allocable vectors;
    VECTOR_FIXED_START/END for fixed allocated vectors, such as vector for
    timer etc.

Signed-off-by: Yan, Like <like.yan@intel.com>
Acked-by: Anthony Xu <anthony.xu@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>

hypervisor/arch/x86/ioapic.c

@@ -372,7 +372,7 @@ void setup_ioapic_irq(void)
 			 * for legacy irq, reserved vector and never free
 			 */
 			if (gsi < NR_LEGACY_IRQ) {
-				vr = irq_desc_alloc_vector(gsi, false);
+				vr = irq_desc_alloc_vector(gsi);
 				if (vr > NR_MAX_VECTOR) {
 					pr_err("failed to alloc VR");
 					gsi++;