GRUB_IEEE1275_FLAG_HAS_CURSORONOFF when appropriate.
* grub-core/term/ieee1275/ofconsole.c (grub_ofconsole_setcursor):
Use terminfo and don't use cursor-on/cursor-off unless it's known
to work.
* include/grub/ieee1275/ieee1275.h (grub_ieee1275_flag): New element
GRUB_IEEE1275_FLAG_HAS_CURSORONOFF.