bus: fsl-mc: dprc: Push down error message from fsl_mc_driver_remove()

The error message emitted in fsl_mc_driver_remove() is very generic.
Replace it by a message that mentions the reason for the failure.

Returning zero instead of a negative value has no side effect apart from
suppressing the generic error message.

The first if condition in dprc_remove() can never be true, as this would
prevent successful probing of the device and then .remove wasn't called.
So this can just be dropped.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Tested-by: Ioana Ciornei <ioana.ciornei@nxp.com> # sanity checks
Reviewed-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Tested-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Signed-off-by: Li Yang <leoyang.li@nxp.com>