spi: sprd: Replace of_hwspin_lock_get_id() with of_hwspin_lock_get_id_byname()

Now the hwlock core has supplied new function to get a specific hwlock id
by one hwlock name, which is more clear for users. So change to use
of_hwspin_lock_get_id_byname().

Acked-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>