PCI: rcar: Fix runtime PM imbalance on error

pm_runtime_get_sync() increments the runtime PM usage counter even
when the call returns an error code. Thus a corresponding decrement is
needed on the error handling path to keep the counter balanced.

Link: https://lore.kernel.org/r/20200709064356.8800-1-dinghao.liu@zju.edu.cn


Fixes: 0df6150e ("PCI: rcar: Use runtime PM to control controller clock")
Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>