pch_phub: Care FUNCSEL register in PM

Only ML7213/ML7223(Bus-n) has this register.
Currently,this driver doesn't care register "FUNCSEL" in suspend/resume.
This patch saves/restores FUNCSEL register only when the device is ML7213 or
ML7223(Bus-n).

Signed-off-by: Tomoya MORINAGA <tomoya-linux@dsn.okisemi.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>