armv8: ls1088a: SPL size reduction

Using changes in this patch we were able to reduce approx 8k
size of u-boot-spl.bin image. Following is breif description of
changes to reduce SPL size:
1. Changes in board/freescale/ls1088a/Makefile to remove
   compilation of eth.c and cpld.c in case of SPL build.
2. Changes in board/freescale/ls1088a/ls1088a.c to keep
   board_early_init_f funcations in case of SPL build.
3. Changes in ls1088a_common.h & ls1088ardb.h to remove driver
   specific macros due to which static data was being compiled in
   case of SPL build.

Signed-off-by: Sumit Garg <sumit.garg@nxp.com>
Reviewed-by: York Sun <york.sun@nxp.com>