firmware: qcom: scm: Remove reassignment to desc following initializer

Member assignments to qcom_scm_desc were moved into struct initializers
in 57d3b816 ("firmware: qcom_scm: Remove thin wrappers") including
the case in qcom_scm_iommu_secure_ptbl_init, except that the - now
duplicate - assignment to desc was left in place. While not harmful,
remove this unnecessary extra reassignment.

Fixes: 57d3b816 ("firmware: qcom_scm: Remove thin wrappers")
Signed-off-by: Marijn Suijten <marijn.suijten@somainline.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@somainline.org>
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20211208083423.22037-2-marijn.suijten@somainline.org