nxp: config_fsl_chain_trust.h: Clean up and remove unused portions

The way that secure boot is implemented today on NXP ARM platforms does
not reuse the elements found in include/config_fsl_chain_trust.h to
construct CONFIG_SECBOOT but instead board header files have their
environment setup as needed and then fsl_setenv_chain_of_trust() will
set secureboot in the environment.  Remove a large number of unused
defines here.

Cc: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Tom Rini <trini@konsulko.com>