Some Linux kernels seems to implement ITLB/UTLB flushing through by
writing all TLB entries through the memory mapped interface instead
of writing one to MMUCR.TI.

Implement memory mapped ITLB write interface so that such kernels can
boot. This fixes https://bugs.launchpad.net/bugs/700774 .
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>