OMAP: ISP1301: Compile fix

Fix this build error on non- OMAP-H2/H3/H4 systems:
(factored out two empty functions as part of the fix)

  CC      drivers/usb/otg/isp1301_omap.o
drivers/usb/otg/isp1301_omap.c: In function 'otg_update_isp':
drivers/usb/otg/isp1301_omap.c:635: error: implicit declaration of function 'notresponding'
drivers/usb/otg/isp1301_omap.c: In function 'b_peripheral':
drivers/usb/otg/isp1301_omap.c:973: error: implicit declaration of function 'enable_vbus_draw'
drivers/usb/otg/isp1301_omap.c: In function 'isp_update_otg':
drivers/usb/otg/isp1301_omap.c:1003: error: implicit declaration of function 'enable_vbus_source'
make[2]: *** [drivers/usb/otg/isp1301_omap.o] Error 1
make[1]: *** [drivers/usb/otg] Error 2
make: *** [drivers] Error 2
Signed-off-by: Anand Gadiyar <gadiyar@ti.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>