shippable.yml: Remove jobs duplicated on Gitlab-CI

shippable.yml: Remove jobs duplicated on Gitlab-CI

The following jobs are duplicated on Gitlab-CI since commit
6bcb5fc0f7a ("gitlab-ci: Add cross-compiling build tests"):

- IMAGE=debian-armel-cross

  TARGET_LIST=arm-softmmu               -> cross-armel-system
  TARGET_LIST=arm-linux-user            -> cross-armel-user
  TARGET_LIST=armeb-linux-user          -> cross-armel-user

- IMAGE=debian-armhf-cross

  TARGET_LIST=arm-softmmu               -> cross-armhf-system
  TARGET_LIST=arm-linux-user            -> cross-armhf-user
  TARGET_LIST=armeb-linux-user          -> cross-armhf-user

- IMAGE=debian-arm64-cross

  TARGET_LIST=aarch64-softmmu           -> cross-arm64-system
  TARGET_LIST=aarch64-linux-user        -> cross-arm64-user

- IMAGE=debian-s390x-cross

  TARGET_LIST=s390x-softmmu             -> cross-s390x-system
  TARGET_LIST=s390x-linux-user          -> cross-s390x-user

- IMAGE=debian-mips-cross

  TARGET_LIST=mipsel-linux-user         -> cross-mips-user

- IMAGE=debian-mips64el-cross

  TARGET_LIST=mips64el-softmmu          -> cross-mips64el-system
  TARGET_LIST=mips64el-linux-user       -> cross-mips64el-user

- IMAGE=debian-ppc64el-cross

  TARGET_LIST=ppc64-softmmu             -> cross-ppc64el-system
  TARGET_LIST=ppc64-linux-user          -> cross-ppc64el-user
  TARGET_LIST=ppc64abi32-linux-user     -> cross-ppc64el-user

Remove them from Shippable CI.

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Acked-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20210108145103.269353-1-f4bug@amsat.org>
Message-Id: <20210114165730.31607-4-alex.bennee@linaro.org>