mtd: cfi_cmdset_0002: Use chip_ready() for write on S29GL064N

Since commit dfeae107("mtd: cfi_cmdset_0002: Change write buffer to
check correct value") buffered writes fail on S29GL064N. This is
because, on S29GL064N, reads return 0xFF at the end of DQ polling for
write completion, where as, chip_good() check expects actual data
written to the last location to be returned post DQ polling completion.
Fix is to revert to using chip_good() for S29GL064N which only checks
for DQ lines to settle down to determine write completion.

Link: https://lore.kernel.org/r/b687c259-6413-26c9-d4c9-b3afa69ea124@pengutronix.de/
Fixes: dfeae107

("mtd: cfi_cmdset_0002: Change write buffer to check correct value")
Cc: stable@vger.kernel.org
Signed-off-by: Tokunori Ikegami <ikegami.t@gmail.com>
Acked-by: Vignesh Raghavendra <vigneshr@ti.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220323170458.5608-3-ikegami.t@gmail.com