drivers: soc: xilinx: add the missing kfree in xlnx_add_cb_for_suspend()

In the Linux kernel, the following vulnerability has been resolved:

drivers: soc: xilinx: add the missing kfree in xlnx_add_cb_for_suspend()

If we fail to allocate memory for cb_data by kmalloc, the memory

allocation for eve_data is never freed, add the missing kfree()

in the error handling path.