x86/irq: Factor out common code for checking pending interrupts

Use a common function for checking pending interrupt vector in APIC IRR
instead of duplicated open coding them.

Additional checks for posted MSI vectors can then be contained in this
function.

Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240423174114.526704-10-jacob.jun.pan@linux.intel.com