imx: imx6ul: kontron-sl-mx6ul: Disable CONFIG_FSL_QSPI_AHB_FULL_MAP to fix SPI NAND...

imx: imx6ul: kontron-sl-mx6ul: Disable CONFIG_FSL_QSPI_AHB_FULL_MAP to fix SPI NAND read access

The introduction of CONFIG_FSL_QSPI_AHB_FULL_MAP as default in:

d67cd3b5e44f ("spi: fsl_qspi: Support to use full AHB space on i.MX")

broke the SPI NAND read access on the Kontron SL i.MX6UL/ULL boards.
Reading data from the flash returns garbage instead of the actual
content. Fix this for now by disabling the introduced option.

In the long run this should be fixed globally.

Fixes: d67cd3b5e44f ("spi: fsl_qspi: Support to use full AHB space on i.MX")
Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Reviewed-by: Fabio Estevam <festevam@denx.de>