usb: chipidea: support runtime power management for otg fsm mode

This patch adds runtime power management support for otg fsm mode, since
A-device in a_idle state cannot detect data pulse irq after suspended, here
enable wakeup by connection before suspend to make it can be resumed by DP;
and handle wakeup from that state like SRP.

Signed-off-by: Li Jun <jun.li@freescale.com>
Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/chipidea/bits.h b/drivers/usb/chipidea/bits.h
index e69424d..3cb9bda 100644
--- a/drivers/usb/chipidea/bits.h
+++ b/drivers/usb/chipidea/bits.h
@@ -63,6 +63,7 @@
 #define PORTSC_HSP            BIT(9)
 #define PORTSC_PP             BIT(12)
 #define PORTSC_PTC            (0x0FUL << 16)
+#define PORTSC_WKCN           BIT(20)
 #define PORTSC_PHCD(d)	      ((d) ? BIT(22) : BIT(23))
 /* PTS and PTW for non lpm version only */
 #define PORTSC_PFSC           BIT(24)