spi: spi-loopback-test: Fix formatting issues in function header blocks

Kerneldoc function parameter descriptions must be in '@.*: ' format.

Fixes the following W=1 kernel build warning(s):

 drivers/spi/spi-loopback-test.c:897: warning: Function parameter or member 'spi' not described in 'spi_test_execute_msg'
 drivers/spi/spi-loopback-test.c:897: warning: Function parameter or member 'test' not described in 'spi_test_execute_msg'
 drivers/spi/spi-loopback-test.c:897: warning: Function parameter or member 'tx' not described in 'spi_test_execute_msg'
 drivers/spi/spi-loopback-test.c:897: warning: Function parameter or member 'rx' not described in 'spi_test_execute_msg'
 drivers/spi/spi-loopback-test.c:970: warning: Function parameter or member 'spi' not described in 'spi_test_run_test'
 drivers/spi/spi-loopback-test.c:970: warning: Function parameter or member 'test' not described in 'spi_test_run_test'
 drivers/spi/spi-loopback-test.c:970: warning: Function parameter or member 'tx' not described in 'spi_test_run_test'
 drivers/spi/spi-loopback-test.c:970: warning: Function parameter or member 'rx' not described in 'spi_test_run_test'
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Martin Sperl <kernel@martin.sperl.org>
Cc: linux-spi@vger.kernel.org
Link: https://lore.kernel.org/r/20200717135424.2442271-2-lee.jones@linaro.orgSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-loopback-test.c

@@ -885,10 +885,10 @@ static int spi_test_run_iter(struct spi_device *spi,
 /**
  * spi_test_execute_msg - default implementation to run a test
  *
- * spi: @spi_device on which to run the @spi_message
- * test: the test to execute, which already contains @msg
- * tx:   the tx buffer allocated for the test sequence
- * rx:   the rx buffer allocated for the test sequence
+ * @spi: @spi_device on which to run the @spi_message
+ * @test: the test to execute, which already contains @msg
+ * @tx:   the tx buffer allocated for the test sequence
+ * @rx:   the rx buffer allocated for the test sequence
  *
  * Returns: error code of spi_sync as well as basic error checking
  */
@@ -957,10 +957,10 @@ EXPORT_SYMBOL_GPL(spi_test_execute_msg);
  *                     including all the relevant iterations on:
  *                     length and buffer alignment
  *
- * spi:  the spi_device to send the messages to
- * test: the test which we need to execute
- * tx:   the tx buffer allocated for the test sequence
- * rx:   the rx buffer allocated for the test sequence
+ * @spi:  the spi_device to send the messages to
+ * @test: the test which we need to execute
+ * @tx:   the tx buffer allocated for the test sequence
+ * @rx:   the rx buffer allocated for the test sequence
  *
  * Returns: status code of spi_sync or other failures
  */