firmware: qcom_scm-legacy: correct kerneldoc

Correct kerneldoc warnings like:

  drivers/firmware/qcom_scm-legacy.c:133:
    warning: Function parameter or member 'dev' not described in 'scm_legacy_call'
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220519073410.7358-1-krzysztof.kozlowski@linaro.org

drivers/firmware/qcom_scm-legacy.c

@@ -120,6 +120,9 @@ static void __scm_legacy_do(const struct arm_smccc_args *smc,
 /**
  * scm_legacy_call() - Sends a command to the SCM and waits for the command to
  * finish processing.
+ * @dev:	device
+ * @desc:	descriptor structure containing arguments and return values
+ * @res:        results from SMC call
  *
  * A note on cache maintenance:
  * Note that any buffers that are expected to be accessed by the secure world
@@ -211,6 +214,7 @@ int scm_legacy_call(struct device *dev, const struct qcom_scm_desc *desc,
 /**
  * scm_legacy_call_atomic() - Send an atomic SCM command with up to 5 arguments
  * and 3 return values
+ * @unused: device, legacy argument, not used, can be NULL
  * @desc: SCM call descriptor containing arguments
  * @res:  SCM call return values
  *