intel_th: make intel_th_bus_type constant

intel_th: make intel_th_bus_type constant

Now that the driver core can properly handle constant struct bus_type,
move the intel_th_bus_type variable to be a constant structure as well,
placing it into read-only memory which can not be modified at runtime.

Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/2025091412-machine-despair-248e@gregkh
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>