doc: replace "practise" with "practice" in Documentation

To keep the Documentation consistent either
"practise" or "practice" should be used.

Since there are 3 lines with "practise"

  ~/linux/Documentation$ grep -r practise * | wc -l
  3

and 108 lines with "practice"

  ~/linux/Documentation$ grep -r practice * | wc -l
  108

this patch converts "practise" to "practice".

Signed-off-by: Jeremiah Mahler <jmmahler@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/Documentation/PCI/MSI-HOWTO.txt b/Documentation/PCI/MSI-HOWTO.txt
index 10a9369..0d920d5 100644
--- a/Documentation/PCI/MSI-HOWTO.txt
+++ b/Documentation/PCI/MSI-HOWTO.txt
@@ -576,7 +576,7 @@
 is handled in the individual device driver, but occasionally it's necessary
 to handle this with a quirk.  Some drivers have an option to disable use
 of MSI.  While this is a convenient workaround for the driver author,
-it is not good practise, and should not be emulated.
+it is not good practice, and should not be emulated.
 
 5.4. Finding why MSIs are disabled on a device