checkpatch: format strings should not have brackets in macros

We should not recommend braces for the following:

    #define pr_fmt(fmt)    "%s: " fmt, __func__

allow things with double quotes round them to avoid this check.

Signed-off-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>