arm: mvebu: Load U-Boot proper binary in SPL code based on kwbimage header

arm: mvebu: Load U-Boot proper binary in SPL code based on kwbimage header

Now that proper load and execution addresses are set in v1 kwbimage we
can use it for loading and booting U-Boot proper.

Use the new spl_parse_board_header() function to implement parsing the
kwbimage v1 header. Use information from this header to locate offset and
size of the U-Boot proper binary, instead of using the legacy U-Boot
header which is prepended to the U-Boot proper binary stored at fixed
offset. This has the advantage that we do not need to relay on legacy
U-Boot header anymore and therefore U-Boot proper binary can be stored at
any offset, as is the case when loading & booting U-Boot proper by
BootROM. The CONFIG_SYS_U_BOOT_OFFS option is therefore not used by SPL
code anymore.

Also allow to compile U-Boot SPL without CONFIG_SPL_SPI_FLASH_SUPPORT,
CONFIG_SPL_MMC_SUPPORT or CONFIG_SPL_SATA_SUPPORT set. In this case
BootROM is used for loading and executing U-Boot proper. This reduces the
size of U-Boot's SPL image. By default these config options are enabled
and so BootROM loading is not used. In some cases BootROM reads from SPI
NOR at lower speed than U-Boot SPL. So people can decide whether they
want to have smaller SPL binary at the cost of slower boot.

Therefore dependency on CONFIG_SPL_DM_SPI, CONFIG_SPL_SPI_FLASH_SUPPORT,
CONFIG_SPL_SPI_LOAD, CONFIG_SPL_SPI_SUPPORT, CONFIG_SPL_DM_GPIO,
CONFIG_SPL_DM_MMC, CONFIG_SPL_GPIO_SUPPORT, CONFIG_SPL_LIBDISK_SUPPORT,
CONFIG_SPL_MMC_SUPPORT, CONFIG_SPL_SATA_SUPPORT and
CONFIG_SPL_LIBDISK_SUPPORT is changed from strict to related "imply"
(which can be selectivelly turned off and causes booting via BootROM).

Options CONFIG_SYS_SPI_U_BOOT_OFFS,
CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR and
CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_DATA_PART_OFFSET have to to be set to
zero as they define the location where kwbimage header starts. It is the
location where BootROM expects start of the kwbimage from which it reads,
parses and executes SPL part. The same applies to option
CONFIG_SPL_SATA_RAW_U_BOOT_SECTOR, which has to be set to one.

Update all config files to set correct values of these options and set
CONFIG_SYS_U_BOOT_OFFS to the correct value - the offset where U-Boot
proper starts.

Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Stefan Roese <sr@denx.de>