Add full support for SPI flash chips to future-proof U-Boot for cm-t43.

Cc: Tom Rini <trini@konsulko.com>
Cc: Albert Aribaud <albert.u.boot@aribaud.net>
Cc: Igor Grinberg <grinberg@compulab.co.il>
Signed-off-by: NNikita Kiryanov <nikita@compulab.co.il>
Reviewed-by: NTom Rini <trini@konsulko.com>

Move CONFIG_DM_SERIAL to cm_t43_defconfig. This forces us to update the
CONFIG_SYS_NS16550_REG_SIZE value for SPL.

Cc: Tom Rini <trini@konsulko.com>
Cc: Albert Aribaud <albert.u.boot@aribaud.net>
Cc: Igor Grinberg <grinberg@compulab.co.il>
Signed-off-by: NNikita Kiryanov <nikita@compulab.co.il>
Reviewed-by: NTom Rini <trini@konsulko.com>

Move CONFIG_SYS_NS16550 to Kconfig, and run moveconfig.py.
Signed-off-by: NThomas Chou <thomas@wytron.com.tw>

Add CMD_GPIO to Kconfig and run tools/moveconfig.py .
Signed-off-by: NThomas Chou <thomas@wytron.com.tw>
Reviewed-by: NSimon Glass <sjg@chromium.org>

Some boards' defconfigs are disordered. Reorder them.
Signed-off-by: NBin Meng <bmeng.cn@gmail.com>

Add initial support for CM-T43, an AM437x based SoM.
This support includes: serial, MMC/eMMC, NAND, USB, ETH, I2C, GPIO, DRAM
detection.

Cc: Tom Rini <trini@konsulko.com>
Cc: Albert Aribaud <albert.u.boot@aribaud.net>
Cc: Igor Grinberg <grinberg@compulab.co.il>
Signed-off-by: NNikita Kiryanov <nikita@compulab.co.il>