PM / devfreq: imx-bus: Fix inconsistent IS_ERR and PTR_ERR

Fix inconsistent IS_ERR and PTR_ERR in imx_bus_init_icc().

The proper pointer to be passed as argument to PTR_ERR() is
priv->icc_pdev.

This bug was detected with the help of Coccinelle.

Fixes: 16c1d2f1b0bd ("PM / devfreq: imx: Register interconnect device")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Dong Aisheng <aisheng.dong@nxp.com>
[cw00.choi: Edit the patch title from 'imx' to 'imx-bus']
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>