binman: Correct '-a' description in the doc

It needs a space around '-a'.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Rick Chen <rick@andestech.com>
This commit is contained in:
Bin Meng 2021-05-10 20:23:30 +08:00 committed by Leo Yu-Chi Liang
parent 6e847f6d5d
commit 2817c9dd32