This is a preparation for changing rq->cmd from the static array to a
pointer.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Boaz Harrosh <bharrosh@panasas.com>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

* Rename ide-cd kernel module to ide-cd_mod in preparation to moving code out
  from ide-cd.[c,h].   Add MODULE_ALIAS("ide-cd") to preserve compatibility.

* Move VERBOSE_IDE_CD_ERRORS code from ide-cd.[c,h] to ide-cd_verbose.c.

  ide-cd_verbose.c is IDE subsystem independent and may be easily converted
  into generic library usable by other drivers (i.e. libata) if needed.

* Add CONFIG_BLK_DEV_IDECD_VERBOSE_ERRORS config option to drivers/ide/Kconfig
  replacing VERBOSE_IDE_CD_ERRORS define.  Make this config option enabled by
  default and visible only if CONFIG_EMBEDDED is defined.

before the patch:
   text    data     bss     dec     hex filename
  22841     360    1056   24257    5ec1 drivers/ide/ide-cd.o

after the patch w/ CONFIG_BLK_DEV_IDECD_VERBOSE_ERRORS=y:
   text    data     bss     dec     hex filename
  22857     360    1056   24273    5ed1 drivers/ide/ide-cd_mod.o

after the patch w/ CONFIG_BLK_DEV_IDECD_VERBOSE_ERRORS=n:
   text    data     bss     dec     hex filename
  15091     360    1056   16507    407b drivers/ide/ide-cd_mod.o

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>