checkpatch: warn on unnecessary parentheses around references of foo->bar

Parentheses around &(foo->bar) and *(foo->bar) are unnecessary.  Emit a
--strict only message on these uses.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>