Documentation: update CodingStyle use of braces

After commit 38829dc9

 ("Documentation/CodingStyle: flesh out if-else
examples") highlight that if _only_one_ branch of a conditional
statement is a single statement, then braces are to be used on both
branches.

Signed-off-by: Antonio Ospite <ospite@studenti.unina.it>
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>