musb-new: Fix reset sequence when in host mode

This commit fixes a number of issues with the reset sequence of musb-new
in host mode:

1) Our usb device probe relies on a second device reset being done after the
first descriptors read. Factor the musb reset code into a usb_reset_root_port
function (and add this as an empty define for other controllers), and call
this when a device has no parent.

2) Just like with normal usb controllers there needs to be a delay after
reset, for normal usb controllers, this is handled in hub_port_reset, add a
delay to usb_reset_root_port.

3) Sync the musb reset sequence with the upstream kernel, clear all bits of
power except bits 4-7, and increase the time reset is asserted to 50 ms.

With these fixes an usb keyboard I have now always enumerates properly, where
as earlier it would only enumerare properly once every 5 tries.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>

include/usb.h

@@ -159,6 +159,11 @@ enum usb_init_type {
 
 int usb_lowlevel_init(int index, enum usb_init_type init, void **controller);
 int usb_lowlevel_stop(int index);
+#ifdef CONFIG_MUSB_HOST
+void usb_reset_root_port(void);
+#else
+#define usb_reset_root_port()
+#endif
 
 int submit_bulk_msg(struct usb_device *dev, unsigned long pipe,
 			void *buffer, int transfer_len);