env: fix cmd_env_sub fct pointers if CONFIG_RELOC_FIXUP_WORKS is not defined

commit ea882baf introduces
a command_sub_table for the "env" command. On arm, avr32, m68k,
mips and sparc architectures, relocation needs manual fixups,
so add these fixups for this sub command table too.

Tested on arm/qong board.
          mips board (Ben NanoNote) from Xiangfu Liu
          arm/AT91 board from Reinhard Meyer

Signed-off-by: Heiko Schocher <hs@denx.de>

cc: Wolfgang Denk <wd@denx.de>
cc: Shinya Kuribayashi <skuribay@ruby.dti.ne.jp>
cc: Xiangfu Liu <xiangfu@openmobilefree.net>
cc: Reinhard Meyer <u-boot@emk-elektronik.de>
cc: sshtylyov@mvista.com