Preparing lowlevel cdrom rewrite
- use #if BX_SUPPORT_CDROM instead of #ifdef LOWLEVEL_CDROM
- devices with cdrom support now use the base class cdrom_base_c
- cdrom count variable moved to cdrom.cc
- cdrom_misc.cc: don't use ioctl's for ISO files


git-svn-id: svn://svn.code.sf.net/p/bochs/code/trunk@11923 6c8e4198-a580-4521-a02f-c9ae86df1db9