mtd: maps: physmap-core: fix flash size larger than 32-bit

[ Upstream commit 3884f03edd34887514a0865a80769cd5362d5c3b ]

mtd-ram can potentially be larger than 4GB. get_bitmask_order() uses
fls() that is not guaranteed to work with values larger than 32-bit.
Specifically on aarch64 fls() returns 0 when all 32 LSB bits are clear.
Use fls64() instead.

Fixes: ba32ce9 ("mtd: maps: Merge gpio-addr-flash.c into physmap-core.c")
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/9fbf3664ce00f8b07867f1011834015f21d162a5.1707388458.git.baruch@tkos.co.il
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/mtd/maps/physmap-core.c

@@ -518,7 +518,7 @@ static int physmap_flash_probe(struct platform_device *dev)
 		if (!info->maps[i].phys)
 			info->maps[i].phys = res->start;
 
-		info->win_order = get_bitmask_order(resource_size(res)) - 1;
+		info->win_order = fls64(resource_size(res)) - 1;
 		info->maps[i].size = BIT(info->win_order +
 					 (info->gpios ?
 					  info->gpios->ndescs : 0));