* kern/disk.c: Replace `<grub/machine/time.h>' with `<grub/time.h>'.
(grub_last_time): Change type to grub_uint64_t.
(grub_disk_open): Migrate code from to using grub_get_time_ms().
(grub_disk_close): Likewise.
* normal/menu.c: Replace `<grub/machine/time.h>' with `<grub/time.h>'.
(run_menu): Migrate code from to using grub_get_time_ms().
* util/misc.c (grub_get_time_ms): New function.