arm64: dts: ti: verdin-am62: Improve spi1 chip-select pinctrl

arm64: dts: ti: verdin-am62: Improve spi1 chip-select pinctrl

Verdin SPI_1 interface has a dedicated hardware controlled chip select
that is currently configured in the same pinctrl group as MISO/MOSI/CLK,
however it is possible that it can be used only as a standard GPIO be it
a chip select or not.

To maximize flexibility and avoid duplication in the carrier board dts
files move the SPI_1 CS in a dedicated pinctrl and also adds an
additional pinctrl to simplify using SPI_1 CS as a GPIO.

Signed-off-by: Joao Paulo Goncalves <joao.goncalves@toradex.com>
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Link: https://lore.kernel.org/r/20231205184605.35225-2-francesco@dolcini.it
Signed-off-by: Nishanth Menon <nm@ti.com>