Fix detection of "real mode" when /options/real-mode? doesn't exist.
* include/grub/ieee1275/ieee1275.h (grub_ieee1275_mmu): New variable
declaration.
* kern/powerpc/ieee1275/cmain.c (grub_ieee1275_mmu): New variable.
(grub_ieee1275_find_options): If `grub_ieee1275_mmu' is 0, set
`GRUB_IEEE1275_FLAG_REAL_MODE'.
(cmain): Intialize `grub_ieee1275_mmu' (using /chosen/mmu integer
property).
* kern/powerpc/ieee1275/openfw.c (grub_map): Rely on pre-initialized
`grub_ieee1275_mmu' rather than obtaining a handler on every call.
0bf74728de