PCI/MSI: Correct misleading comments

PCI/MSI: Correct misleading comments

commit 689e6b5351573c38ccf92a0dd8b3e2c2241e4aff upstream.

The comments about preserving the cached state in pci_msi[x]_shutdown() are
misleading as the MSI descriptors are freed right after those functions
return. So there is nothing to restore. Preparatory change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210729222542.621609423@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>