USB: usb-stor: realtek_cr: Fix compile error

To fix the compile error when CONFIG_PM_RUNTIME is not enabled,
move the declaration of us out of CONFIG_REALTEK_AUTOPM macro in rts51x_chip.

drivers/usb/storage/realtek_cr.c: In function 'realtek_cr_destructor':
drivers/usb/storage/realtek_cr.c:942:11: error: 'struct rts51x_chip' has no member named 'us'

Signed-off-by: Wei WANG <wei_wang@realsil.com.cn>
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>