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 <[email protected]>
Signed-off-by: Jiri Kosina <[email protected]>

Documentation/PCI/MSI-HOWTO.txt

@@ -576,7 +576,7 @@ Some devices are known to have faulty MSI implementations.  Usually this
 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
 

Documentation/SubmittingPatches

@@ -369,13 +369,13 @@ you are responsible for last-minute changes. Example :
 	[[email protected]: struct foo moved from foo.c to foo.h]
 	Signed-off-by: Lucky K Maintainer <[email protected]>
 
-This practise is particularly helpful if you maintain a stable branch and
+This practice is particularly helpful if you maintain a stable branch and
 want at the same time to credit the author, track changes, merge the fix,
 and protect the submitter from complaints. Note that under no circumstances
 can you change the author's identity (the From header), as it is the one
 which appears in the changelog.
 
-Special note to back-porters: It seems to be a common and useful practise
+Special note to back-porters: It seems to be a common and useful practice
 to insert an indication of the origin of a patch at the top of the commit
 message (just after the subject line) to facilitate tracking. For instance,
 here's what we see in 2.6-stable :