usb: chipidea: debug: fix sparse non static symbol warnings

Fixes the following sparse warnings:

drivers/usb/chipidea/debug.c:211:5: warning:
symbol 'ci_otg_show' was not declared. Should it be static?
drivers/usb/chipidea/debug.c:334:5: warning:
symbol 'ci_registers_show' was not declared. Should it be static?

Signed-off-by: Wei Yongjun <[e-mail]>
Signed-off-by: Peter Chen <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/chipidea/debug.c

···
 	.release	= single_release,
 };
 
-int ci_otg_show(struct seq_file *s, void *unused)
+static int ci_otg_show(struct seq_file *s, void *unused)
 {
 	struct ci_hdrc *ci = s->private;
 	struct otg_fsm *fsm;
···
 	.release	= single_release,
 };
 
-int ci_registers_show(struct seq_file *s, void *unused)
+static int ci_registers_show(struct seq_file *s, void *unused)
 {
 	struct ci_hdrc *ci = s->private;
 	u32 tmp_reg;