x86/hyperv: Expose hv_map_msi_interrupt()

Move some of the logic of hv_irq_compose_irq_message() into
hv_map_msi_interrupt(). Make hv_map_msi_interrupt() a globally-available
helper function, which will be used to map PCI interrupts when running
in the root partition.

Signed-off-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
Signed-off-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Reviewed-by: Roman Kisel <romank@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Link: https://lore.kernel.org/r/1752261532-7225-3-git-send-email-nunodasneves@linux.microsoft.com


Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <1752261532-7225-3-git-send-email-nunodasneves@linux.microsoft.com>