block/partitions/efi.c: consistently use pr_foo()

Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: Karel Zak <kzak@redhat.com>
Cc: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>