ARM: socfpga: boot0 hook: remove macro from boot0 header file

Commit ce62e57f ("ARM: boot0 hook: remove macro, include whole
header file") miss out cleaning macro in this header file, and this
has broken implementation of a boot header capability in socfpga
SPL. Remove the macro in this file, and recovering it back
to proper functioning.

Fixes: ce62e57f ("ARM: boot0 hook: remove macro, include whole
header file")

Signed-off-by: Chee, Tien Fong <tien.fong.chee@intel.com>