USB: OTG: msm: Fix compiler warning with CONFIG_PM disabled

This patch fixes the below compiler warning

drivers/usb/otg/msm72k_otg.c:257: warning: 'msm_otg_suspend' defined but not used

Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>