PCI: Fix whitespace, capitalization, and spelling errors

Fix whitespace, capitalization, and spelling errors.  No functional change.
I know "busses" is not an error, but "buses" was more common, so I used it
consistently.

Signed-off-by: Marta Rybczynska <rybczynska@gmail.com> (pci_reset_bridge_secondary_bus())
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 5e63645..3fcd67a 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -784,7 +784,7 @@
  * @nvec: how many MSIs have been requested ?
  * @type: are we checking for MSI or MSI-X ?
  *
- * Look at global flags, the device itself, and its parent busses
+ * Look at global flags, the device itself, and its parent buses
  * to determine if MSI/-X are supported for the device. If MSI/-X is
  * supported return 0, else return an error code.
  **/