Fix a gcc 12 warning about a narrowing conversion in case labels for
tape options.
> In file included from /wip/cygwin/src/winsup/cygwin/include/sys/mtio.h:14,
> from ../../../../src/winsup/cygwin/fhandler/tape.cc:13:
> ../../../../src/winsup/cygwin/fhandler/tape.cc: In member function ‘int mtinfo_drive::set_options(HANDLE, int32_t)’:
> ../../../../src/winsup/cygwin/fhandler/tape.cc:965:12: error: narrowing conversion of ‘4026531840’ from ‘unsigned int’ to ‘int’ [-Wnarrowing]
Signed-off-by: Jon Turney <jon.turney@dronecode.org.uk>