mtd: spi-nor: Rewrite rem_bank_len calculation

Rewrite the code to make it clear exactly where the
SNOR_F_HAS_PARALLEL flag leads to *2 and /2 operation
compared to regular code path. No functional change.

Fixes: 5d40b3d384dc ("mtd: spi-nor: Add parallel and stacked memories support")
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
1 file changed