Add file wifi_mod_para_powersave.conf which include
powersave_enable flag. Add logic in wifi driver which
can parse this flag.
Add append_bootargs:
setenv append_bootargs moal.mod_para=wifi_mod_para_powersave.conf
saveenv
Change-Id: If0875510385219e47f9b74c4b64b11701849db6c
Signed-off-by: zhipeng.wang <zhipeng.wang_1@nxp.com>