bus: fsl-mc: mc-io: Correct misdocumentation of 'dpmcp_dev' param

bus: fsl-mc: mc-io: Correct misdocumentation of 'dpmcp_dev' param

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

 drivers/bus/fsl-mc/mc-io.c:70: warning: Function parameter or member 'dpmcp_dev' not described in 'fsl_create_mc_io'

Cc: Stuart Yoder <stuyoder@gmail.com>
Reviewed-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20210617110500.15907-8-lee.jones@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>