board: starfive: function to read eMMC size

The EEPROM provides information about the size of the eMMC.
Provide a new function get_mmc_size_from_eeprom() to read it.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: E. Shattow <lucent@gmail.com>
3 files changed