checkpatch: clean up structure definition macro handline

Handle definitions such as the following correctly, it is not
a complex statement:

    #define PREALLOC(NAME, START, END, FLAGS) {     \
		    .name = (NAME),                 \
		    .start = (START),               \
		    .end = (END),                   \
		    .flags = (FLAGS)                \
	    },

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>