usb: gadget: eliminate anonymous module_init & module_exit

usb: gadget: eliminate anonymous module_init & module_exit

Eliminate anonymous module_init() and module_exit(), which can lead to
confusion or ambiguity when reading System.map, crashes/oops/bugs,
or an initcall_debug log.

Give each of these init and exit functions unique driver-specific
names to eliminate the anonymous names.

Example 1: (System.map)
 ffffffff832fc78c t init
 ffffffff832fc79e t init
 ffffffff832fc8f8 t init

Example 2: (initcall_debug log)
 calling  init+0x0/0x12 @ 1
 initcall init+0x0/0x12 returned 0 after 15 usecs
 calling  init+0x0/0x60 @ 1
 initcall init+0x0/0x60 returned 0 after 2 usecs
 calling  init+0x0/0x9a @ 1
 initcall init+0x0/0x9a returned 0 after 74 usecs

Fixes: bd25a14edb75 ("usb: gadget: legacy/serial: allow dynamic removal")
Fixes: 7bb5ea54be47 ("usb gadget serial: use composite gadget framework")
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Cc: Felipe Balbi <felipe.balbi@linux.intel.com>
Cc: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: linux-usb@vger.kernel.org
Link: https://lore.kernel.org/r/20220316192010.19001-7-rdunlap@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>