misc/mei: Decouple ME interfaces from GPU drivers

misc/mei: Decouple ME interfaces from GPU drivers

These are enumerated via an auxiliary bus, so there is no functional
dependency between these drivers, therefore allow compiling MEI as builtin
even when i915/xe are built as modules.

Cc: Usyskin, Alexander <alexander.usyskin@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Simon Richter <Simon.Richter@hogyros.de>
Link: https://patch.msgid.link/20260107182615.488194-3-Simon.Richter@hogyros.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>