ARM: dts: stm32: Repair SD1 pre-reloc pinmux DT node on AV96

The sdmmc1_dir_pins_a: sdmmc1-dir-0 layout changed in commit 35a54d41
("ARM: dts: stm32mp1: sync device tree with v5.2-rc4") such that pins{};
became pins1{};pins2{};, however the SPL extras were not updated to reflect
that change. Fix this.

This fixes booting from SD1 X9 slot on the AV96 board.

Reviewed-by: Patrice Chotard <patrice.chotard@st.com>
Reviewed-by: Patrick Delaunay <patrick.delaunay@st.com>
Fixes: 35a54d41 ("ARM: dts: stm32mp1: sync device tree with v5.2-rc4")
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: Patrick Delaunay <patrick.delaunay@st.com>
Cc: Patrice Chotard <patrice.chotard@st.com>