USB: Remove unneeded void * casts in core files

The patch removes unneeded casts for the following (void *) pointers:
 - struct file: private
 - struct urb: context
 - struct usb_bus: hcpriv
 - return value of kmalloc()

The patch also contains some whitespace cleanup in the relevant areas.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/core/urb.c b/drivers/usb/core/urb.c
index 5769199..9801d08e 100644
--- a/drivers/usb/core/urb.c
+++ b/drivers/usb/core/urb.c
@@ -57,7 +57,7 @@
 {
 	struct urb *urb;
 
-	urb = (struct urb *)kmalloc(sizeof(struct urb) + 
+	urb = kmalloc(sizeof(struct urb) +
 		iso_packets * sizeof(struct usb_iso_packet_descriptor),
 		mem_flags);
 	if (!urb) {