The CONFIG_SPL_MAX_SIZE could be 0x27000 for i.MX8MM when SPL_TEXT_BASE
set to 0x7E1000.
The DDR firmware max uses 96KB, there is a 4KB padding header before
SPL_TEXT_BASE, so the SPL MAX SIZE is `256KB - 96KB - 4KB`.
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Fabio Estevam <festevam@denx.de>