mtd: rawnand: qcom: update last code word register

From QPIC v2 onwards a new register got added to read last
code word.Add support for this READ_LOCATION_LAST_CW_n
register.

In the case of QPIC v2, codewords 0, 1 and 2 will be accessed
through READ_LOCATION_n, while codeword 3 will be accessed
through READ_LOCATION_LAST_CW_n.

Signed-off-by: Md Sadre Alam <mdalam@codeaurora.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/1614109141-7531-5-git-send-email-mdalam@codeaurora.org