arm: ls1046ardb: Add SD secure boot target

- Add SD secure boot target for ls1046ardb.
- Change the u-boot size defined by a macro for copying the main
  U-Boot by SPL to also include the u-boot Secure Boot header size
  as header is appended to u-boot image. So header will also be
  copied from SD to DDR.
- CONFIG_MAX_SPL_SIZE is limited to 90KB. SPL is copied to OCRAM
  (128K) where 32K are reserved for use by boot ROM and 6K for the
  header.
- Reduce the size of CAAM driver for SPL Blobification functions
  and descriptors, that are not required at the time of SPL are
  disabled. Further error code conversion to strings is disabled
  for SPL build.

Signed-off-by: Vinitha Pillai <vinitha.pillai@nxp.com>
Signed-off-by: Sumit Garg <sumit.garg@nxp.com>
Signed-off-by: Ruchika Gupta <ruchika.gupta@nxp.com>
Reviewed-by: York Sun <york.sun@nxp.com>