USB: musb: make HAVE_CLK support optional

The Blackfin port doesn't support HAVE_CLK and the musb driver works fine
with support stubbed out, so take the existing Blackfin clk stubs and move
them to common musb code so we can drop the Kconfig dependency.

Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/musb/Kconfig b/drivers/usb/musb/Kconfig
index 803adcb..760e727 100644
--- a/drivers/usb/musb/Kconfig
+++ b/drivers/usb/musb/Kconfig
@@ -8,7 +8,7 @@
 
 # (M)HDRC = (Multipoint) Highspeed Dual-Role Controller
 config USB_MUSB_HDRC
-	depends on (USB || USB_GADGET) && HAVE_CLK
+	depends on (USB || USB_GADGET)
 	depends on !SUPERH
 	select NOP_USB_XCEIV if ARCH_DAVINCI
 	select TWL4030_USB if MACH_OMAP_3430SDP