When we press ctrl-alt-del,kernel_restart_prepare will invoke 
cfi_intelext_reboot which will set flash to read array mode, but later 
when device_shutdown is invoked which may put current work queue to 
sleep and other process may be scheduled to running and programming 
flash in not FL_READY mode again. So we can't boot up if this flash is 
used for bootloader.
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>