Move CONFIG_CSF_SIZE to Kconfig and define default value as 0x4000.

mx8mqevk requires 0x2000 add this configuration in imx8mq_evk_defconfig
file.
Signed-off-by: NBreno Lima <breno.lima@nxp.com>
Reviewed-by: NFabio Estevam <festevam@gmail.com>