pciehp: remove unnecessary pci_disable_msi

This patch fixes the problem that "irq XX: nobody cared" kernel oops
is reported when pciehp is once rmmoded and insmoded again. The cause
of this problem is pciehp driver calls pci_disable_msi() at controller
release time, even though it must be done by PCI Express Port Bus
driver. This patch removes unnecessary pci_disable_msi() call from
pciehp driver.

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>