rtw88: include interrupt.h for tasklet_struct

Depending on implicit header includes, we might see this compilation
error:

.../main.h:1391:24: error: field has incomplete type 'struct tasklet_struct'
        struct tasklet_struct tx_tasklet;
                              ^

Fixes: 3745d3e5 ("rtw88: add driver TX queue support")
Signed-off-by: Brian Norris <briannorris@chromium.org>
Acked-by: Yan-Hsuan Chuang <yhchuang@realtek.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>