mtd: rawnand: qcom: Add read/read_start ops in exec_op path

READ/READ_START opcodes are not set in exec_op path.
Fixing that here.

While there, Steps to program the controller is common for
erase/reset/read/program page. So use a common pattern and
pull them under one function.

Signed-off-by: Md Sadre Alam <quic_mdalam@quicinc.com>
Signed-off-by: Sricharan Ramabadhran <quic_srichara@quicinc.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20230818145101.23825-4-quic_mdalam@quicinc.com