low-level-can-service fix: Yocto compile failed

low-level-can-service fix: Yocto compile failed

Cherry picked commit 85099f34f7c15f041c84b541cb121be5ab7c61a2

Can't set compile FLAG using set using Yocto build

If set, then these are the flags that are used by bitbake
without append its own flags which provides toolchain
variables
environment mandatory to correctly build for another
target.

Change-Id: Iccf0ea5de401c0ee77ad864a381fb1137c047d48
Signed-off-by: Romain Forlot <romain.forlot@iot.bzh>
Reviewed-on: https://gerrit.automotivelinux.org/gerrit/10561
ci-image-build: Jenkins Job builder account <agl-jobbuilder@automotivelinux.org>
Reviewed-by: José Bollo <jobol@nonadev.net>
Reviewed-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>
Tested-by: Jenkins Job builder account <agl-jobbuilder@automotivelinux.org>
ci-image-boot-test: Jenkins Job builder account <agl-jobbuilder@automotivelinux.org>