[flash_ctrl,lint] Waive a width warning for NumBanks * PagesPerBank
[flash_ctrl,lint] Waive a width warning for NumBanks * PagesPerBank

Signed-off-by: Rupert Swarbrick <290093e2ad2515ed2f14d749293c8cf8e02ca274@lowrisc.org>

lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan