i2c: cadence: Fix power management order of operations

E.g. pm_runtime_set_active must be called while the power
management system is disabled. Fixes extra hanging clk_enable.

Signed-off-by: Topi Kuutela <topi.kuutela@gmail.com>
Acked-by: Sören Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>