mtd: rawnand: qcom: Add helper to configure location register

Create a nandc_set_read_loc() helper to abstract the
configuration of the location register.

QPIC v2 onwards features a separate location register
for the last codeword, so introducing this extra helper
which will simplify the addition of QPIC v2 support.

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/1614109141-7531-4-git-send-email-mdalam@codeaurora.org