staging: fsl-mc/dpio: remove unused function

gcc warns that function 'qbman_pull_desc_set_token' is not used.

drivers/staging/fsl-mc/bus/dpio/qbman-portal.c:525:13: warning: ‘qbman_pull_desc_set_token’ defined but not used [-Wunused-function]

In the current code we remove that function.

Fixes: 321eecb0

 ("bus: fsl-mc: dpio: add QBMan portal APIs for DPAA2")
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>