platform/x86: intel_pmc_ipc: Use devm_* calls in driver probe function

This patch cleans up unnecessary free/alloc calls in ipc_plat_probe(),
ipc_pci_probe() and ipc_plat_get_res() functions by using devm_*
calls.

This patch also adds proper error handling for failure cases in
ipc_pci_probe() function.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
[andy: fixed style issues, missed devm_free_irq(), removed unnecessary log message]
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>