toybox源码编译时，默认会进行strip操作，如下步骤：

//third_party/toybox/scripts/make.sh:340:
! do_loudly ${CROSS_COMPILE}${STRIP} "$UNSTRIPPED" -o "$OUTNAME"

因此在打包的Makefile中再进行STRIP操作是冗余的。

close #I43767

Change-Id: I10a9861b682eb8e556b7af7519c9109eef0b3a94
Signed-off-by: NGuangyao Ma <guangyao.ma@outlook.com>