mtd: rawnand: davinci: Remove redundant unsigned comparison to zero

Since core_chipsel is uint32_t, comparison to zero is redundant

Signed-off-by: Wang Weiyang <wangweiyang2@huawei.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220317113907.96006-1-wangweiyang2@huawei.com