usb: ehci-msm-hsic: Fix compilation error

The ehci-msm-hsic driver's bus suspend and resume functions
depend on ehci_hcd's bus_suspend/resume functions, which are
NULL when CONFIG_PM is not defined. Fix the compilation error
by also #defining these sub-driver functions NULL, as they
are effectively no-ops.

Change-Id: Ie250dfae3caccb737ce26bdda17c5b21d358eced
Signed-off-by: Jack Pham <jackp@codeaurora.org>
diff --git a/drivers/usb/host/ehci-msm-hsic.c b/drivers/usb/host/ehci-msm-hsic.c
index b7f1878..ac39c07 100644
--- a/drivers/usb/host/ehci-msm-hsic.c
+++ b/drivers/usb/host/ehci-msm-hsic.c
@@ -926,6 +926,8 @@
 	return 0;
 }
 
+#ifdef CONFIG_PM
+
 static int ehci_hsic_bus_suspend(struct usb_hcd *hcd)
 {
 	struct msm_hsic_hcd *mehci = hcd_to_hsic(hcd);
@@ -1135,6 +1137,13 @@
 	return 0;
 }
 
+#else
+
+#define ehci_hsic_bus_suspend	NULL
+#define ehci_hsic_bus_resume	NULL
+
+#endif	/* CONFIG_PM */
+
 static struct hc_driver msm_hsic_driver = {
 	.description		= hcd_name,
 	.product_desc		= "Qualcomm EHCI Host Controller using HSIC",