ARM: dts: imx25-pinfunc: Use consistent naming for eSDHC

This file had several naming inconsistencies for eSDHC:
 - the instances were named sometimes SDn, sometimes SDHCn, whereas they
   are named ESDHCn in the reference manual, e.g.:
     MX25_PAD_SD1_CMD__SD1_CMD
     MX25_PAD_D15__SDHC1_DAT7
 - the data ports were named sometimes DATAn, sometimes DATn like in the
   reference manual, e.g.:
     MX25_PAD_SD1_DATA0__SD1_DATA0
     MX25_PAD_D15__SDHC1_DAT7
 - in one case, the clock port was named DAT_CLK instead of CLK:
     MX25_PAD_CSI_D7__SDHC2_DAT_CLK

This change:
 - introduces new definitions using the naming from the reference
   manual,
 - keeps definitions using the legacy naming in order not to break
   compatibility for out-of-tree users (they can be removed later),
 - updates the in-tree files that were using the legacy naming.

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau.dev@gmail.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>