ARM: dts: imx6ull-pinfunc: Fix CSI_DATA07__ESAI_TX0 pad name

According to the i.MX6ULL Reference Manual, pad CSI_DATA07 may
have the ESAI_TX0 functionality, not ESAI_T0.

Also, NXP's i.MX Config Tools 10.0 generates dtsi with the
MX6ULL_PAD_CSI_DATA07__ESAI_TX0 naming, so fix it accordingly.

There are no devicetree users in mainline that use the old name,
so just remove the old entry.

Fixes: c201369d ("ARM: dts: imx6ull: add imx6ull support")
Reported-by: George Makarov <georgemakarov1@gmail.com>
Signed-off-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>