docs: kernel-doc: fix parsing of arrays

The logic with parses array has a bug that prevents it to
parse arrays like:
	struct {
	...
		struct {
			u64 msdu[IEEE80211_NUM_TIDS + 1];
			...
	...

Fix the parser to accept it.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>