Proper U-Boot for Lichee Pi 4A now runs in S mode instead of M mode,
which means the extra firmware, OpenSBI, must be built and integrated
in the image, and the vendor U-Boot cannot chainload the result image
anymore as it runs in M mode.

Remove redundant information about chainloading and update build steps
to mention OpenSBI firmware.

Signed-off-by: Yao Zi <ziyao@disroot.org>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>

Support for eMMC, SD card, GPIO and SPL have been available in LPi4A
port. Update the documentation of support status and build
instructions.

Signed-off-by: Yao Zi <ziyao@disroot.org>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>

Title underlines should match the length of the title. Unfortunately
docutils only catches underlines that are too short.

Add some missing empty lines after titles.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>

Reviewed-by: Wei Fu <wefu@redhat.com>
Signed-off-by: Yixun Lan <dlan@gentoo.org>