build: fix some compiler warnings

Most of them catched on 32bit gcc and icc.

disk-utils/fsck.cramfs.c:     printf format type
lib/boottime.c:               unused variables
misc-utils/cal.c:             set but never used
sys-utils/losetup.c:          set but never used
sys-utils/lscpu-dmi.c:        defined but not used
sys-utils/switch_root.c:      comparison between signed and unsigned
tests/helpers/test_sysinfo.c: printf format type
Merge branch 'warnings-squashed' of https://github.com/rudimeier/util-linux

* 'warnings-squashed' of https://github.com/rudimeier/util-linux:
  build: fix some compiler warnings
libblkid: (zfs) let's keep compiler happy

Signed-off-by: Karel Zak <kzak@redhat.com>