kernel-doc: handle/strip __init

Handle __init in functions with kernel-doc notation by stripping the
__init away from the output doc.  This is already being done for
"__devinit".  This patch fixes these kernel-doc error/aborts:

Error(linux-next-20080619//drivers/usb/gadget/config.c:132): cannot understand prototype: 'struct usb_descriptor_header **__init usb_copy_descriptors(struct usb_descriptor_header **src) '
Error(linux-next-20080619//drivers/usb/gadget/config.c:182): cannot understand prototype: 'struct usb_endpoint_descriptor *__init usb_find_endpoint( 	struct usb_descriptor_header **src, 	struct usb_descriptor_header **copy, 	struct usb_endpoint_descriptor *match ) '

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>