mtd: nand: qcom: fix read failure without complete bootchain

mtd: nand: qcom: fix read failure without complete bootchain

commit d8a9b320a26c1ea28e51e4f3ecfb593d5aac2910 upstream.

The NAND page read fails without complete boot chain since
NAND_DEV_CMD_VLD value is not proper. The default power on reset
value for this register is

    0xe - ERASE_START_VALID | WRITE_START_VALID | READ_STOP_VALID

The READ_START_VALID should be enabled for sending PAGE_READ
command. READ_STOP_VALID should be cleared since normal NAND
page read does not require READ_STOP command.

Fixes: c76b78d8ec05a ("mtd: nand: Qualcomm NAND controller driver")
Reviewed-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Abhishek Sahu <absahu@codeaurora.org>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>