mt76: mt7915: fix potential overflow of eeprom page index

mt76: mt7915: fix potential overflow of eeprom page index

[ Upstream commit 82a980f82a511ce74ab57eb9f692d02225eb32f4 ]

If total eeprom size is divisible by per-page size, the i in for loop
will exceed max page index, which happens in our newer chipset.

Fixes: 26f18380e6ca ("mt76: mt7915: add support for flash mode")
Signed-off-by: Bo Jiao <bo.jiao@mediatek.com>
Signed-off-by: Shayne Chen <shayne.chen@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Sasha Levin <sashal@kernel.org>