rtlwifi: fix spelling typo of workaround

workarould -> workaround

Signed-off-by: Wang Qing <wangqing@vivo.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/1604738439-24794-1-git-send-email-wangqing@vivo.com