usb: storagE: realtek_cr: fix sparse warnings

usb: storagE: realtek_cr: fix sparse warnings

Fix the following sparse warnings:

| drivers/usb/storage/realtek_cr.c:821:6: warning: symbol
|	'rts51x_invoke_transport' was not declared. Should
|	it be static?
|
| drivers/usb/storage/realtek_cr.c:980:5: warning: symbol
|	'realtek_cr_suspend' was not declared. Should it
|	be static?
|
| drivers/usb/storage/realtek_cr.c:518:23: warning: cast
|	truncates bits from constant value (fe47 becomes 47)

Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>