s390/pci: Do not mask MSI[-X] entries on teardown

The PCI core already ensures that the MSI[-X] state is correct when MSI[-X]
is disabled. For MSI the reset state is all entries unmasked and for MSI-X
all vectors are masked.

S390 masks all MSI entries and masks the already masked MSI-X entries
again. Remove it and let the device in the correct state.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Niklas Schnelle <schnelle@linux.ibm.com>
Tested-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Acked-by: Niklas Schnelle <schnelle@linux.ibm.com>
Link: https://lore.kernel.org/r/20210729222542.939798136@linutronix.de