USB: Mark EHCI LPM functions as __maybe_unused

ehci_lpm_set_da and ehci_lpm_check are EHCI 1.1 specific functions which
are not used on many platforms but do generate annoying gcc warnings
Signed-off-by: Maksim Rayskiy <mrayskiy@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/host/ehci-lpm.c

@@ -17,7 +17,8 @@
 */
 
 /* this file is part of ehci-hcd.c */
-static int ehci_lpm_set_da(struct ehci_hcd *ehci, int dev_addr, int port_num)
+static int __maybe_unused ehci_lpm_set_da(struct ehci_hcd *ehci,
+	int dev_addr, int port_num)
 {
 	u32 __iomem portsc;
 
@@ -37,7 +38,7 @@ static int ehci_lpm_set_da(struct ehci_hcd *ehci, int dev_addr, int port_num)
  * this function is used to check if the device support LPM
  * if yes, mark the PORTSC register with PORT_LPM bit
  */
-static int ehci_lpm_check(struct ehci_hcd *ehci, int port)
+static int __maybe_unused ehci_lpm_check(struct ehci_hcd *ehci, int port)
 {
 	u32 __iomem	*portsc ;
 	u32 val32;