platform/x86: Revert intel_pmc_ipc: Use MFD framework to create dependent devices

Heikki discovered a runtime issue with this patch. Taking into
consideration we have no time to test any fix right now, revert the
commit 43aaf4f0.

Reported-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>