wifi: mwifiex: fix memory leak in mwifiex_histogram_read()

wifi: mwifiex: fix memory leak in mwifiex_histogram_read()

[ Upstream commit 9c8fd72a5c2a031cbc680a2990107ecd958ffcdb ]

Always free the zeroed page on return from 'mwifiex_histogram_read()'.

Fixes: cbf6e05527a7 ("mwifiex: add rx histogram statistics support")
Acked-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230802160726.85545-1-dmantipov@yandex.ru
Signed-off-by: Sasha Levin <sashal@kernel.org>