arm64: dts: Add DSPI entries for S32G platforms

arm64: dts: Add DSPI entries for S32G platforms

S32G3 and S32G2 have the same 6 SPI devices, add the DT entries. Devices
are all the same except spi0 has 8 chip selects instead of 5. Clock
settings for the chip rely on ATF Firmware [1].

[1]: https://github.com/nxp-auto-linux/arm-trusted-firmware
Co-developed-by: Radu Pirea (NXP OSS) <radu-nicolae.pirea@oss.nxp.com>
Signed-off-by: Radu Pirea (NXP OSS) <radu-nicolae.pirea@oss.nxp.com>
Signed-off-by: Larisa Grigore <Larisa.Grigore@nxp.com>
Signed-off-by: James Clark <james.clark@linaro.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>