headers/deps: USB: Optimize <linux/usb/ch9.h> dependencies, remove <linux/device.h>

The <linux/usb/ch9.h> header is used over 1,400 times in a typical distro
build, but few of its users actually need the full <linux/device.h> header.

--------------------------------------------------------------------
| Combined, preprocessed C code size of header, without line markers,
| with comments stripped:
-------------------------
before: | #include <linux/usb/ch9.h> | LOC: 7,078 | headers: 172
after: | #include <linux/usb/ch9.h> | LOC: 812 | headers: 38

Remove it and add it to the places that need it.

Signed-off-by: Ingo Molnar <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

include/linux/usb/ch9.h

···
 #ifndef __LINUX_USB_CH9_H
 #define __LINUX_USB_CH9_H
 
-#include <linux/device.h>
 #include <uapi/linux/usb/ch9.h>
 
 /* USB 3.2 SuperSpeed Plus phy signaling rate generation and lane count */
···
 	USB_SSP_GEN_1x2,
 	USB_SSP_GEN_2x2,
 };
+
+struct device;
 
 extern const char *usb_ep_type_string(int ep_type);
 extern const char *usb_speed_string(enum usb_device_speed speed);