mmc: sdhci-esdhc-imx: Update esdhc sysctl dtocv bitmask

NXP ESDHC supports setting data timeout using uSDHCx_SYS_CTRL register
DTOCV bits (bits 16-19).
Currently the driver accesses those bits by 32-bit write using
SDHCI_TIMEOUT_CONTROL (0x2E) defined in drivers/mmc/host/sdhci.h.
This is offset by two bytes relative to uSDHCx_SYS_CTRL (0x2C).
The driver also defines ESDHC_SYS_CTRL_DTOCV_MASK as first 4 bits, which
is correct relative to SDHCI_TIMEOUT_CONTROL but not relative to
uSDHCx_SYS_CTRL. The definition carrying control register in its name is
therefore inconsistent.

Update the bitmask definition for bits 16-19 to be correct relative to
control register base.
Update the esdhc_set_timeout function to set timeout value at control
register base, not timeout offset.

This solves a purely cosmetic problem.

Signed-off-by: Josua Mayer <josua@solid-run.com>
Reviewed-by: Haibo Chen <haibo.chen@nxp.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Message-ID: <20241101-imx-emmc-reset-v3-2-184965eed476@solid-run.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>