p2sb: Move P2SB hide and unhide code to p2sb_scan_and_cache()

To prepare for the following fix, move the code to hide and unhide the
P2SB device from p2sb_cache_resources() to p2sb_scan_and_cache().

Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20241128002836.373745-4-shinichiro.kawasaki@wdc.com


Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>